<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2023 Workiva-->
<!--r:302f3ae3-a75e-4419-9133-437bb0f6322d,g:f9eefa8d-9e3c-4992-a0f5-96e8f06722ac-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/ConsolidatedStatementsofFinancialCondition" xlink:type="simple" xlink:href="amal-20230930.xsd#ConsolidatedStatementsofFinancialCondition"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/ConsolidatedStatementsofFinancialCondition" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_2e0c2cb0-fc47-4dfa-9ddb-51c3cc7ab96a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2e0c2cb0-fc47-4dfa-9ddb-51c3cc7ab96a" xlink:to="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndDueFromBanks_eaacdfb5-5ff5-4f5c-9f43-6024fdec431b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndDueFromBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_CashAndDueFromBanks_eaacdfb5-5ff5-4f5c-9f43-6024fdec431b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestBearingDepositsInBanks_41beb306-83b5-46dc-83eb-fb89e00fd852" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestBearingDepositsInBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_InterestBearingDepositsInBanks_41beb306-83b5-46dc-83eb-fb89e00fd852" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_f3fc777b-f954-4045-b8e9-2970d1951790" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_f3fc777b-f954-4045-b8e9-2970d1951790" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAbstract_5b3c6d29-b453-4102-95d1-84c85a7cfab8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_DebtSecuritiesAbstract_5b3c6d29-b453-4102-95d1-84c85a7cfab8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_461fe11c-fe91-4e79-a6f0-04e2ed995569" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAbstract_5b3c6d29-b453-4102-95d1-84c85a7cfab8" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_461fe11c-fe91-4e79-a6f0-04e2ed995569" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_b19ff352-26a2-4bce-b9dd-82e4ed68f968" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAbstract_5b3c6d29-b453-4102-95d1-84c85a7cfab8" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_b19ff352-26a2-4bce-b9dd-82e4ed68f968" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_41472993-1ca1-4cdf-bf73-75a91f6b2609" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_LoansReceivableHeldForSaleNetNotPartOfDisposalGroup_41472993-1ca1-4cdf-bf73-75a91f6b2609" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_9d19cac5-8d22-45b8-8353-a4658e0486bb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_9d19cac5-8d22-45b8-8353-a4658e0486bb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_1bed614b-0a84-4253-a2ff-1ec7d3dafadf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_1bed614b-0a84-4253-a2ff-1ec7d3dafadf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_ee9c816f-c446-4e80-bc72-29cb46aeed8c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_ee9c816f-c446-4e80-bc72-29cb46aeed8c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesPurchasedUnderAgreementsToResell_4b2cec4a-0dd0-456a-b565-bf3ea0a2fd07" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SecuritiesPurchasedUnderAgreementsToResell"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_SecuritiesPurchasedUnderAgreementsToResell_4b2cec4a-0dd0-456a-b565-bf3ea0a2fd07" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankStock_875ed6b5-9727-4ecf-848a-bd7f91f87fb6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_FederalHomeLoanBankStock_875ed6b5-9727-4ecf-848a-bd7f91f87fb6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NontradeReceivables_062225a4-f818-4fd8-9958-07831569c6d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NontradeReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_NontradeReceivables_062225a4-f818-4fd8-9958-07831569c6d7" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_1da374b5-fdca-4f27-aacb-a3bb10115e66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_1da374b5-fdca-4f27-aacb-a3bb10115e66" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankOwnedLifeInsurance_26452e41-73a1-44e1-814a-674c4fe409b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BankOwnedLifeInsurance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_BankOwnedLifeInsurance_26452e41-73a1-44e1-814a-674c4fe409b6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_8771ee4f-a4e8-4f05-9929-a2189ff800d3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_8771ee4f-a4e8-4f05-9929-a2189ff800d3" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_a091395f-3fd9-462e-af87-4ba10f2a4b4d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_a091395f-3fd9-462e-af87-4ba10f2a4b4d" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_570e20dc-b103-4993-94d1-032f9eb4a8c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_Goodwill_570e20dc-b103-4993-94d1-032f9eb4a8c7" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsNet_571f566e-adfc-4cb9-ae3b-3a5cdf2c674d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_OtherIntangibleAssetsNet_571f566e-adfc-4cb9-ae3b-3a5cdf2c674d" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_f4bf130a-7e0b-4a05-ae3e-33f6571f058f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_EquityMethodInvestments_f4bf130a-7e0b-4a05-ae3e-33f6571f058f" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_5cb9a861-9a4c-4378-8f53-3b7dd637e33e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_OtherAssets_5cb9a861-9a4c-4378-8f53-3b7dd637e33e" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_f8e345d0-e1eb-41ea-8f20-2c0717fc90b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_4a0a7e62-4277-492f-873b-7acae48d87a9" xlink:to="loc_us-gaap_Assets_f8e345d0-e1eb-41ea-8f20-2c0717fc90b2" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2e0c2cb0-fc47-4dfa-9ddb-51c3cc7ab96a" xlink:to="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Deposits_ebe5d9b9-ab82-4110-b46a-02a3d968be28" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Deposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_Deposits_ebe5d9b9-ab82-4110-b46a-02a3d968be28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebt_05ef86a0-abb0-431c-b28d-8311b0d78299" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubordinatedDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_SubordinatedDebt_05ef86a0-abb0-431c-b28d-8311b0d78299" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_e85c8b07-d151-4e90-9217-5df960813688" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankAdvancesLongTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_e85c8b07-d151-4e90-9217-5df960813688" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherBorrowings_6b1dd9ec-142f-4c30-94b1-63e63458fc24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_OtherBorrowings_6b1dd9ec-142f-4c30-94b1-63e63458fc24" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_54681f6d-9c40-455c-9da0-d50a4bfff5a4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_OperatingLeaseLiability_54681f6d-9c40-455c-9da0-d50a4bfff5a4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_bd35cf3b-676f-435f-aed6-103c85d1dd45" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_OtherLiabilities_bd35cf3b-676f-435f-aed6-103c85d1dd45" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_19ee48b4-53a2-4db7-a1e5-64950ce1b019" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_cc632bdd-25e6-49bf-abce-11b2899665d8" xlink:to="loc_us-gaap_Liabilities_19ee48b4-53a2-4db7-a1e5-64950ce1b019" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2e0c2cb0-fc47-4dfa-9ddb-51c3cc7ab96a" xlink:to="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_e095c1b2-14f9-4fc7-88e7-2b97943ea52a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_CommonStockValue_e095c1b2-14f9-4fc7-88e7-2b97943ea52a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_51df202c-00d1-47d8-bab1-6127f91174dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_AdditionalPaidInCapital_51df202c-00d1-47d8-bab1-6127f91174dd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_34d1550c-516e-4031-92a2-3d1a971bbd57" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_34d1550c-516e-4031-92a2-3d1a971bbd57" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_f21a4e81-b5c7-493a-8668-07c34d5e5d61" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_f21a4e81-b5c7-493a-8668-07c34d5e5d61" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonValue_8cf9777c-089e-417a-9cfb-5ab25ad0cb47" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_TreasuryStockCommonValue_8cf9777c-089e-417a-9cfb-5ab25ad0cb47" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_a35345ae-54a1-43a0-b9b6-1770d671a16d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_StockholdersEquity_a35345ae-54a1-43a0-b9b6-1770d671a16d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_3ec50821-a2a6-488e-9a5a-95762a7442b4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_MinorityInterest_3ec50821-a2a6-488e-9a5a-95762a7442b4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_32ddc8ed-81b8-4568-a509-a20156ec390c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_462c42b8-a851-4fd6-a6c9-70931040ed2c" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_32ddc8ed-81b8-4568-a509-a20156ec390c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_1d2c32e1-3770-432b-8e57-52fa5819cfe3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_2e0c2cb0-fc47-4dfa-9ddb-51c3cc7ab96a" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_1d2c32e1-3770-432b-8e57-52fa5819cfe3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_eba7da8d-cc6a-4e70-9de2-147353100693" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_2e0c2cb0-fc47-4dfa-9ddb-51c3cc7ab96a" xlink:to="loc_us-gaap_StatementTable_eba7da8d-cc6a-4e70-9de2-147353100693" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_11962588-70e2-4400-b4bf-78eed08bf229" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_eba7da8d-cc6a-4e70-9de2-147353100693" xlink:to="loc_us-gaap_FinancialInstrumentAxis_11962588-70e2-4400-b4bf-78eed08bf229" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_11962588-70e2-4400-b4bf-78eed08bf229_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_11962588-70e2-4400-b4bf-78eed08bf229" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_11962588-70e2-4400-b4bf-78eed08bf229_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6e9ec8a0-9937-450b-b0ee-b0a0d1c4bf91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_11962588-70e2-4400-b4bf-78eed08bf229" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6e9ec8a0-9937-450b-b0ee-b0a0d1c4bf91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CollateralizedTraditionalSecuritiesMember_a61a316f-35f5-45b1-a75d-83a7f83717a5" xlink:href="amal-20230930.xsd#amal_CollateralizedTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6e9ec8a0-9937-450b-b0ee-b0a0d1c4bf91" xlink:to="loc_amal_CollateralizedTraditionalSecuritiesMember_a61a316f-35f5-45b1-a75d-83a7f83717a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_8ac8c43d-05f4-44bb-876d-b7b455e52c8a" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6e9ec8a0-9937-450b-b0ee-b0a0d1c4bf91" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_8ac8c43d-05f4-44bb-876d-b7b455e52c8a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/ConsolidatedStatementsofFinancialConditionParenthetical" xlink:type="simple" xlink:href="amal-20230930.xsd#ConsolidatedStatementsofFinancialConditionParenthetical"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/ConsolidatedStatementsofFinancialConditionParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_a4bc4749-202c-4843-ac93-d24d09c04330" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_a4bc4749-202c-4843-ac93-d24d09c04330" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_d6f1b28b-cd04-4bfe-8d89-783005f3f4d0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_d6f1b28b-cd04-4bfe-8d89-783005f3f4d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_62447cbd-1977-4d7e-8aa0-3f77e543033c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_62447cbd-1977-4d7e-8aa0-3f77e543033c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_ef4dbb23-3442-4df3-a0da-c0b86d20334b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_CommonStockSharesIssued_ef4dbb23-3442-4df3-a0da-c0b86d20334b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_70952e28-aea1-43df-aa55-f9d6778e0b10" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_70952e28-aea1-43df-aa55-f9d6778e0b10" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_099ab68c-3138-4746-b293-e92df80722c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_TreasuryStockCommonShares_099ab68c-3138-4746-b293-e92df80722c6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_df551994-d7b4-48d9-a002-0d4184357460" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_70b13d69-80c0-4fee-aba5-a26c5a265fe6" xlink:to="loc_us-gaap_StatementTable_df551994-d7b4-48d9-a002-0d4184357460" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_a05cdcfe-08cd-4c56-912b-16a228a7db7f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_df551994-d7b4-48d9-a002-0d4184357460" xlink:to="loc_us-gaap_FinancialInstrumentAxis_a05cdcfe-08cd-4c56-912b-16a228a7db7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a05cdcfe-08cd-4c56-912b-16a228a7db7f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_a05cdcfe-08cd-4c56-912b-16a228a7db7f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a05cdcfe-08cd-4c56-912b-16a228a7db7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cbc2ece5-aa31-4ce5-9c52-cc7dabfcfe9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_a05cdcfe-08cd-4c56-912b-16a228a7db7f" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cbc2ece5-aa31-4ce5-9c52-cc7dabfcfe9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CommercialTraditionalSecuritiesMember_d7dff874-0ed0-480f-8045-3d3826072e5f" xlink:href="amal-20230930.xsd#amal_CommercialTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cbc2ece5-aa31-4ce5-9c52-cc7dabfcfe9e" xlink:to="loc_amal_CommercialTraditionalSecuritiesMember_d7dff874-0ed0-480f-8045-3d3826072e5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_b6178c54-28b7-4107-aa67-a5d088577390" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cbc2ece5-aa31-4ce5-9c52-cc7dabfcfe9e" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_b6178c54-28b7-4107-aa67-a5d088577390" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/ConsolidatedStatementsofChangesinStockholdersEquityunaudited" xlink:type="simple" xlink:href="amal-20230930.xsd#ConsolidatedStatementsofChangesinStockholdersEquityunaudited"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/ConsolidatedStatementsofChangesinStockholdersEquityunaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_bad9318d-b3e2-4cdd-8d16-78d60d5f4ac5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_bad9318d-b3e2-4cdd-8d16-78d60d5f4ac5" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_8bfa76d4-69ad-454d-8e27-6c884f9986dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_8bfa76d4-69ad-454d-8e27-6c884f9986dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_38f8e32c-671a-4751-9bcc-bccc7a2d8fbb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_38f8e32c-671a-4751-9bcc-bccc7a2d8fbb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_192da6a5-560c-4b2d-9880-2329af63daf0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_NetIncomeLoss_192da6a5-560c-4b2d-9880-2329af63daf0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_1abc35bf-8c86-4c68-835f-2fa2dfb67f92" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_1abc35bf-8c86-4c68-835f-2fa2dfb67f92" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_041d8876-0b58-4f68-bff4-6ffb67d35fcc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_041d8876-0b58-4f68-bff4-6ffb67d35fcc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_b4a8d80e-d73b-4452-88ff-68946a6cd127" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_b4a8d80e-d73b-4452-88ff-68946a6cd127" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_3fd5f132-b0fa-44cf-83e5-400598fd5260" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_3fd5f132-b0fa-44cf-83e5-400598fd5260" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_073d7897-78ae-4c63-8360-7d0fdc780db2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_DividendsCommonStockCash_073d7897-78ae-4c63-8360-7d0fdc780db2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_a8f5bd9c-c1b9-4ee0-81b5-30c6bc8e8ec9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_a8f5bd9c-c1b9-4ee0-81b5-30c6bc8e8ec9" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_6da39474-7945-4532-8ce5-f450486df018" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_6da39474-7945-4532-8ce5-f450486df018" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfRepurchases_d0333505-0683-40a9-9777-0ae62b4803d9" xlink:href="amal-20230930.xsd#amal_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfRepurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_amal_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfRepurchases_d0333505-0683-40a9-9777-0ae62b4803d9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfRepurchases_1c73d81e-065f-4d9f-ac94-e28a03d7707f" xlink:href="amal-20230930.xsd#amal_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfRepurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_amal_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfRepurchases_1c73d81e-065f-4d9f-ac94-e28a03d7707f" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_feb860dd-120b-4927-b4c6-c9c59ef2a8b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_feb860dd-120b-4927-b4c6-c9c59ef2a8b2" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_6c9542c0-c148-47cf-9d97-8162fb8c38fc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_6c9542c0-c148-47cf-9d97-8162fb8c38fc" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_d28533f1-5069-4743-8a66-17000649e168" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_4928e17e-ade2-44f4-980d-69302cd03e67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdateExtensibleList_161a256a-743f-4cdb-b845-e22e06c49060" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdateExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_cd20cf4e-3f2b-4393-bdd8-e4adfe620c5b" xlink:to="loc_us-gaap_AccountingStandardsUpdateExtensibleList_161a256a-743f-4cdb-b845-e22e06c49060" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_3ef71d93-9502-4bd0-b2b5-92ee7f444fe4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_bad9318d-b3e2-4cdd-8d16-78d60d5f4ac5" xlink:to="loc_us-gaap_StatementTable_3ef71d93-9502-4bd0-b2b5-92ee7f444fe4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f6fefe53-d3cd-484f-943d-1171d9e14e9f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3ef71d93-9502-4bd0-b2b5-92ee7f444fe4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f6fefe53-d3cd-484f-943d-1171d9e14e9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f6fefe53-d3cd-484f-943d-1171d9e14e9f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f6fefe53-d3cd-484f-943d-1171d9e14e9f" xlink:to="loc_us-gaap_EquityComponentDomain_f6fefe53-d3cd-484f-943d-1171d9e14e9f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6f845ee0-361b-4caa-b157-491248a3c4a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f6fefe53-d3cd-484f-943d-1171d9e14e9f" xlink:to="loc_us-gaap_EquityComponentDomain_6f845ee0-361b-4caa-b157-491248a3c4a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6f845ee0-361b-4caa-b157-491248a3c4a8" xlink:to="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_5b5f83d8-67b8-49a2-bcbd-d39fbf6dbcab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:to="loc_us-gaap_CommonStockMember_5b5f83d8-67b8-49a2-bcbd-d39fbf6dbcab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_c56f2c51-5367-46e3-9b09-74ab00084f7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_c56f2c51-5367-46e3-9b09-74ab00084f7c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_71896d66-35c3-41c8-a52d-b9c72b7766ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:to="loc_us-gaap_RetainedEarningsMember_71896d66-35c3-41c8-a52d-b9c72b7766ef" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a1a7d934-bdbc-4e12-b4cb-aa337192e2fb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a1a7d934-bdbc-4e12-b4cb-aa337192e2fb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_5105ab21-c1dc-45ca-921c-45672b8a8c24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_b869e7a9-1ce1-40ab-825d-e1c84b2001dd" xlink:to="loc_us-gaap_TreasuryStockCommonMember_5105ab21-c1dc-45ca-921c-45672b8a8c24" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_c3ade9bc-8c02-4433-80b9-f7a285330f41" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6f845ee0-361b-4caa-b157-491248a3c4a8" xlink:to="loc_us-gaap_NoncontrollingInterestMember_c3ade9bc-8c02-4433-80b9-f7a285330f41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c0586881-e938-4ca5-906e-25c6f8510fd8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3ef71d93-9502-4bd0-b2b5-92ee7f444fe4" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c0586881-e938-4ca5-906e-25c6f8510fd8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_c0586881-e938-4ca5-906e-25c6f8510fd8_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c0586881-e938-4ca5-906e-25c6f8510fd8" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_c0586881-e938-4ca5-906e-25c6f8510fd8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a48a321f-15d1-4a1c-8660-7399a0205c94" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c0586881-e938-4ca5-906e-25c6f8510fd8" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a48a321f-15d1-4a1c-8660-7399a0205c94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_fd94e5c6-87fc-4854-af94-0a8158ad531a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a48a321f-15d1-4a1c-8660-7399a0205c94" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_fd94e5c6-87fc-4854-af94-0a8158ad531a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_532c03ad-ffee-4d34-b208-5dc6ca65a2a7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a48a321f-15d1-4a1c-8660-7399a0205c94" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_532c03ad-ffee-4d34-b208-5dc6ca65a2a7" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/BASISOFPRESENTATIONANDCONSOLIDATIONNarrativeDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#BASISOFPRESENTATIONANDCONSOLIDATIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/BASISOFPRESENTATIONANDCONSOLIDATIONNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_d0f918b6-e3f8-42aa-9931-e7764d49384e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_be3c8d47-be9d-4ba4-8cb6-4023861df1fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_d0f918b6-e3f8-42aa-9931-e7764d49384e" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_be3c8d47-be9d-4ba4-8cb6-4023861df1fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_bc52ae1b-8804-44bf-be16-6822c25dc517" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_d0f918b6-e3f8-42aa-9931-e7764d49384e" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_bc52ae1b-8804-44bf-be16-6822c25dc517" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_63d58a24-9bcd-43d1-9b37-ff94fdb8010c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_d0f918b6-e3f8-42aa-9931-e7764d49384e" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_63d58a24-9bcd-43d1-9b37-ff94fdb8010c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_0652c4df-2a0b-439a-ad34-a376bde06517" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_63d58a24-9bcd-43d1-9b37-ff94fdb8010c" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_0652c4df-2a0b-439a-ad34-a376bde06517" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_0652c4df-2a0b-439a-ad34-a376bde06517_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_0652c4df-2a0b-439a-ad34-a376bde06517" xlink:to="loc_us-gaap_EquityComponentDomain_0652c4df-2a0b-439a-ad34-a376bde06517_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f6e85fd9-8857-4305-ab4b-219357397d09" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_0652c4df-2a0b-439a-ad34-a376bde06517" xlink:to="loc_us-gaap_EquityComponentDomain_f6e85fd9-8857-4305-ab4b-219357397d09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_41a37287-e0c0-4782-ad4e-928150ae5f31" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f6e85fd9-8857-4305-ab4b-219357397d09" xlink:to="loc_us-gaap_RetainedEarningsMember_41a37287-e0c0-4782-ad4e-928150ae5f31" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2fb985a7-aa57-4da6-a7fa-7a0c925ac5a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_63d58a24-9bcd-43d1-9b37-ff94fdb8010c" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2fb985a7-aa57-4da6-a7fa-7a0c925ac5a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_2fb985a7-aa57-4da6-a7fa-7a0c925ac5a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2fb985a7-aa57-4da6-a7fa-7a0c925ac5a8" xlink:to="loc_us-gaap_TypeOfAdoptionMember_2fb985a7-aa57-4da6-a7fa-7a0c925ac5a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_96b5caca-f486-4879-977e-afc99bb42e1e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2fb985a7-aa57-4da6-a7fa-7a0c925ac5a8" xlink:to="loc_us-gaap_TypeOfAdoptionMember_96b5caca-f486-4879-977e-afc99bb42e1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201613Member_30c33595-ddea-44a9-a1a7-ce5f2660a557" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate201613Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_96b5caca-f486-4879-977e-afc99bb42e1e" xlink:to="loc_us-gaap_AccountingStandardsUpdate201613Member_30c33595-ddea-44a9-a1a7-ce5f2660a557" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_b28b9712-ddc5-44dc-9655-9f9ad5d884dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_63d58a24-9bcd-43d1-9b37-ff94fdb8010c" xlink:to="loc_us-gaap_FinancialInstrumentAxis_b28b9712-ddc5-44dc-9655-9f9ad5d884dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b28b9712-ddc5-44dc-9655-9f9ad5d884dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b28b9712-ddc5-44dc-9655-9f9ad5d884dc" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b28b9712-ddc5-44dc-9655-9f9ad5d884dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_df062cd0-de05-467d-b7b0-01e32e0298ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b28b9712-ddc5-44dc-9655-9f9ad5d884dc" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_df062cd0-de05-467d-b7b0-01e32e0298ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansMember_7dc12b45-a986-407d-855e-4203ec267790" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_df062cd0-de05-467d-b7b0-01e32e0298ed" xlink:to="loc_us-gaap_LoansMember_7dc12b45-a986-407d-855e-4203ec267790" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesMember_f1c33dea-f849-42fe-a4aa-6bdef5beb32f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_df062cd0-de05-467d-b7b0-01e32e0298ed" xlink:to="loc_us-gaap_DebtSecuritiesMember_f1c33dea-f849-42fe-a4aa-6bdef5beb32f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/BASISOFPRESENTATIONANDCONSOLIDATIONAdoptionofASUDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#BASISOFPRESENTATIONANDCONSOLIDATIONAdoptionofASUDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/BASISOFPRESENTATIONANDCONSOLIDATIONAdoptionofASUDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_986e432c-89a6-41c8-81ae-2d970a2863ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:to="loc_us-gaap_AssetsAbstract_986e432c-89a6-41c8-81ae-2d970a2863ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_fe630c19-8447-42c6-ada2-24ac91d1539c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_986e432c-89a6-41c8-81ae-2d970a2863ca" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_fe630c19-8447-42c6-ada2-24ac91d1539c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_6e22e0f0-dd69-4789-9eaa-658bc408794f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_986e432c-89a6-41c8-81ae-2d970a2863ca" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_6e22e0f0-dd69-4789-9eaa-658bc408794f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_2921a1d5-d097-4fdd-9228-4e27f777d699" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:to="loc_us-gaap_LiabilitiesAbstract_2921a1d5-d097-4fdd-9228-4e27f777d699" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiability_2780b6c5-ac4b-4693-9c20-3a5694269846" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OffBalanceSheetCreditLossLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_2921a1d5-d097-4fdd-9228-4e27f777d699" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiability_2780b6c5-ac4b-4693-9c20-3a5694269846" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AllowanceForCreditLossExcludingAccruedInterest_5e7bea5f-76cc-44d5-b3ac-0654103f9ce0" xlink:href="amal-20230930.xsd#amal_AllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:to="loc_amal_AllowanceForCreditLossExcludingAccruedInterest_5e7bea5f-76cc-44d5-b3ac-0654103f9ce0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AccountingStandardsUpdateTaxImpactAbstract_37695278-3770-411d-ad2f-faecfb6e6011" xlink:href="amal-20230930.xsd#amal_AccountingStandardsUpdateTaxImpactAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:to="loc_amal_AccountingStandardsUpdateTaxImpactAbstract_37695278-3770-411d-ad2f-faecfb6e6011" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterestTax_9d85656b-d5ab-43fa-9028-edf422d7fb61" xlink:href="amal-20230930.xsd#amal_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterestTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AccountingStandardsUpdateTaxImpactAbstract_37695278-3770-411d-ad2f-faecfb6e6011" xlink:to="loc_amal_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterestTax_9d85656b-d5ab-43fa-9028-edf422d7fb61" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestTax_ea34dedf-4691-481e-9657-d25bfa24ff30" xlink:href="amal-20230930.xsd#amal_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AccountingStandardsUpdateTaxImpactAbstract_37695278-3770-411d-ad2f-faecfb6e6011" xlink:to="loc_amal_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestTax_ea34dedf-4691-481e-9657-d25bfa24ff30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_OffBalanceSheetCreditLossLiabilityTax_6dc4a5ed-726a-478d-9640-bef979ad3372" xlink:href="amal-20230930.xsd#amal_OffBalanceSheetCreditLossLiabilityTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AccountingStandardsUpdateTaxImpactAbstract_37695278-3770-411d-ad2f-faecfb6e6011" xlink:to="loc_amal_OffBalanceSheetCreditLossLiabilityTax_6dc4a5ed-726a-478d-9640-bef979ad3372" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_05ed8966-7562-4a9a-afe6-17a97d66db5a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AccountingStandardsUpdateTaxImpactAbstract_37695278-3770-411d-ad2f-faecfb6e6011" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_05ed8966-7562-4a9a-afe6-17a97d66db5a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_137daed5-b18b-4e18-bf20-515fdb53b2dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_137daed5-b18b-4e18-bf20-515fdb53b2dc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_18cb06a1-a0cb-4d65-bc00-5ff9b3e83b13" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_0ead9a88-9dce-4c5c-9435-4c5fe7034f6f" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_18cb06a1-a0cb-4d65-bc00-5ff9b3e83b13" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_40d85ab5-1a2b-4764-a85e-55367b60bf3c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_18cb06a1-a0cb-4d65-bc00-5ff9b3e83b13" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_40d85ab5-1a2b-4764-a85e-55367b60bf3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_40d85ab5-1a2b-4764-a85e-55367b60bf3c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_40d85ab5-1a2b-4764-a85e-55367b60bf3c" xlink:to="loc_us-gaap_EquityComponentDomain_40d85ab5-1a2b-4764-a85e-55367b60bf3c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d26b418b-c1a1-4ef8-b638-1ffb348036c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_40d85ab5-1a2b-4764-a85e-55367b60bf3c" xlink:to="loc_us-gaap_EquityComponentDomain_d26b418b-c1a1-4ef8-b638-1ffb348036c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_9966a0c1-9b69-4392-be51-038ab7231fd2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d26b418b-c1a1-4ef8-b638-1ffb348036c7" xlink:to="loc_us-gaap_RetainedEarningsMember_9966a0c1-9b69-4392-be51-038ab7231fd2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_86390ccb-2f6b-4971-8d23-5aad39612100" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_18cb06a1-a0cb-4d65-bc00-5ff9b3e83b13" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_86390ccb-2f6b-4971-8d23-5aad39612100" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_86390ccb-2f6b-4971-8d23-5aad39612100_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_86390ccb-2f6b-4971-8d23-5aad39612100" xlink:to="loc_us-gaap_TypeOfAdoptionMember_86390ccb-2f6b-4971-8d23-5aad39612100_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_8b923be8-0077-4743-85ad-fa83c45ba065" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_86390ccb-2f6b-4971-8d23-5aad39612100" xlink:to="loc_us-gaap_TypeOfAdoptionMember_8b923be8-0077-4743-85ad-fa83c45ba065" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201613Member_6fb64d05-51e7-4266-98d5-41598595d5ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate201613Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_8b923be8-0077-4743-85ad-fa83c45ba065" xlink:to="loc_us-gaap_AccountingStandardsUpdate201613Member_6fb64d05-51e7-4266-98d5-41598595d5ae" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofAccumulatedComprehensiveLossDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofAccumulatedComprehensiveLossDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSSummaryofAccumulatedComprehensiveLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_02883c10-5e07-4c5a-aaeb-8d2cc396da79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_2cafd120-dd51-45b6-9faa-ef70867cca06" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_02883c10-5e07-4c5a-aaeb-8d2cc396da79" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_2cafd120-dd51-45b6-9faa-ef70867cca06" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_bce20cc8-016f-4109-bf52-38ac69381795" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_2cafd120-dd51-45b6-9faa-ef70867cca06" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_bce20cc8-016f-4109-bf52-38ac69381795" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_d8b6f05f-a1bf-4bc2-a79a-29bfde14d2a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_2cafd120-dd51-45b6-9faa-ef70867cca06" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_d8b6f05f-a1bf-4bc2-a79a-29bfde14d2a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_d6e58f1b-43dd-4ace-9e5e-4a1d200e1811" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_2cafd120-dd51-45b6-9faa-ef70867cca06" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_d6e58f1b-43dd-4ace-9e5e-4a1d200e1811" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_141c537b-a73c-4a1b-ad82-ba1f36ad5e0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_91f602be-0a22-4995-8d97-dd5b72f9c21c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_02883c10-5e07-4c5a-aaeb-8d2cc396da79" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_91f602be-0a22-4995-8d97-dd5b72f9c21c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_186da6b6-0991-4936-bea9-5ef4708a6cec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_91f602be-0a22-4995-8d97-dd5b72f9c21c" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_186da6b6-0991-4936-bea9-5ef4708a6cec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_186da6b6-0991-4936-bea9-5ef4708a6cec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_186da6b6-0991-4936-bea9-5ef4708a6cec" xlink:to="loc_us-gaap_EquityComponentDomain_186da6b6-0991-4936-bea9-5ef4708a6cec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3350f977-683c-46a1-90b8-4e7afed958e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_186da6b6-0991-4936-bea9-5ef4708a6cec" xlink:to="loc_us-gaap_EquityComponentDomain_3350f977-683c-46a1-90b8-4e7afed958e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_837908b8-b685-4ee4-bb9e-cac1ec30d1c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3350f977-683c-46a1-90b8-4e7afed958e5" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_837908b8-b685-4ee4-bb9e-cac1ec30d1c0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_0dec703a-dca6-4e71-9391-cdaf560d86eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_837908b8-b685-4ee4-bb9e-cac1ec30d1c0" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_0dec703a-dca6-4e71-9391-cdaf560d86eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_e98e6990-5b40-425f-8b41-fcd249833e26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_837908b8-b685-4ee4-bb9e-cac1ec30d1c0" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_e98e6990-5b40-425f-8b41-fcd249833e26" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesHeldToMaturityTransferredParentMember_10549149-87bc-4ce4-a835-af1819d4e085" xlink:href="amal-20230930.xsd#amal_AOCIAccumulatedGainLossDebtSecuritiesHeldToMaturityTransferredParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_837908b8-b685-4ee4-bb9e-cac1ec30d1c0" xlink:to="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesHeldToMaturityTransferredParentMember_10549149-87bc-4ce4-a835-af1819d4e085" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSScheduleofOtherComprehensiveLossDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSScheduleofOtherComprehensiveLossDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSScheduleofOtherComprehensiveLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_62888e3f-d9f3-4085-97de-12948115a168" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_62888e3f-d9f3-4085-97de-12948115a168" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_dce6dae4-caf9-4678-8e8c-a55645c44c1a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_dce6dae4-caf9-4678-8e8c-a55645c44c1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_8b3bfbf6-b1d4-4076-a920-fef4878a372d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_8b3bfbf6-b1d4-4076-a920-fef4878a372d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_418f9307-a59e-481c-a40f-c1cb255f1608" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_418f9307-a59e-481c-a40f-c1cb255f1608" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_ba9e0229-6135-4723-a29a-3264844f2c38" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_ba9e0229-6135-4723-a29a-3264844f2c38" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4bcefcb7-9e1c-4ea3-b393-a4d6ed477baa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_f5f06dad-5c03-4bde-b0ce-2aa5410fc0cb" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4bcefcb7-9e1c-4ea3-b393-a4d6ed477baa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_64423a23-9155-4426-a204-e0f9807cfe1c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4bcefcb7-9e1c-4ea3-b393-a4d6ed477baa" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_64423a23-9155-4426-a204-e0f9807cfe1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_64423a23-9155-4426-a204-e0f9807cfe1c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_64423a23-9155-4426-a204-e0f9807cfe1c" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_64423a23-9155-4426-a204-e0f9807cfe1c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_34d2d742-76d9-4760-b372-6de2c4e99dbd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_64423a23-9155-4426-a204-e0f9807cfe1c" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_34d2d742-76d9-4760-b372-6de2c4e99dbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PostemploymentRetirementBenefitsMember_a8e83b5d-45d5-4cad-9ea3-a019bb948549" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PostemploymentRetirementBenefitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_34d2d742-76d9-4760-b372-6de2c4e99dbd" xlink:to="loc_us-gaap_PostemploymentRetirementBenefitsMember_a8e83b5d-45d5-4cad-9ea3-a019bb948549" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_7e91505e-f4d1-4a09-bebb-90e1c7d4ec5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_34d2d742-76d9-4760-b372-6de2c4e99dbd" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_7e91505e-f4d1-4a09-bebb-90e1c7d4ec5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_9e2e5292-37ed-4033-8f9b-8823029fc406" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4bcefcb7-9e1c-4ea3-b393-a4d6ed477baa" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_9e2e5292-37ed-4033-8f9b-8823029fc406" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_9e2e5292-37ed-4033-8f9b-8823029fc406_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9e2e5292-37ed-4033-8f9b-8823029fc406" xlink:to="loc_us-gaap_EquityComponentDomain_9e2e5292-37ed-4033-8f9b-8823029fc406_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6740d19c-83e3-4954-b337-06b8589e55df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9e2e5292-37ed-4033-8f9b-8823029fc406" xlink:to="loc_us-gaap_EquityComponentDomain_6740d19c-83e3-4954-b337-06b8589e55df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_9bf60756-b87b-4727-8514-4c9ecc512433" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6740d19c-83e3-4954-b337-06b8589e55df" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_9bf60756-b87b-4727-8514-4c9ecc512433" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_15a1574b-9122-4d34-83b7-15e9e9a269ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_9bf60756-b87b-4727-8514-4c9ecc512433" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_15a1574b-9122-4d34-83b7-15e9e9a269ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_5f5ea894-bdee-40f4-b2bf-37e57064f150" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_15a1574b-9122-4d34-83b7-15e9e9a269ed" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_5f5ea894-bdee-40f4-b2bf-37e57064f150" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_a861ab9e-e107-4f1a-83a5-8ae79cca5d7a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_15a1574b-9122-4d34-83b7-15e9e9a269ed" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_a861ab9e-e107-4f1a-83a5-8ae79cca5d7a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesAvailableForSaleAndDebtSecuritiesHeldToMaturityTransferredParentMember_43641425-a5af-40db-970e-5639b93b95f6" xlink:href="amal-20230930.xsd#amal_AOCIAccumulatedGainLossDebtSecuritiesAvailableForSaleAndDebtSecuritiesHeldToMaturityTransferredParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_15a1574b-9122-4d34-83b7-15e9e9a269ed" xlink:to="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesAvailableForSaleAndDebtSecuritiesHeldToMaturityTransferredParentMember_43641425-a5af-40db-970e-5639b93b95f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesExcludingOtherThanTemporaryLossParentMember_15f4050f-d41a-4507-87a0-3234be61365d" xlink:href="amal-20230930.xsd#amal_AOCIAccumulatedGainLossDebtSecuritiesExcludingOtherThanTemporaryLossParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesAvailableForSaleAndDebtSecuritiesHeldToMaturityTransferredParentMember_43641425-a5af-40db-970e-5639b93b95f6" xlink:to="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesExcludingOtherThanTemporaryLossParentMember_15f4050f-d41a-4507-87a0-3234be61365d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesRealizedGainLossOnSaleMember_128fd625-2900-4325-af51-661b1b3bd528" xlink:href="amal-20230930.xsd#amal_AOCIAccumulatedGainLossDebtSecuritiesRealizedGainLossOnSaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesAvailableForSaleAndDebtSecuritiesHeldToMaturityTransferredParentMember_43641425-a5af-40db-970e-5639b93b95f6" xlink:to="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesRealizedGainLossOnSaleMember_128fd625-2900-4325-af51-661b1b3bd528" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesHeldToMaturityTransferredParentMember_c0857a52-fedc-41ad-8b89-0fcc67fd07fd" xlink:href="amal-20230930.xsd#amal_AOCIAccumulatedGainLossDebtSecuritiesHeldToMaturityTransferredParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesAvailableForSaleAndDebtSecuritiesHeldToMaturityTransferredParentMember_43641425-a5af-40db-970e-5639b93b95f6" xlink:to="loc_amal_AOCIAccumulatedGainLossDebtSecuritiesHeldToMaturityTransferredParentMember_c0857a52-fedc-41ad-8b89-0fcc67fd07fd" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAmortizedCostandFairValueofAFSSecuritiesDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#INVESTMENTSECURITIESAmortizedCostandFairValueofAFSSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAmortizedCostandFairValueofAFSSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_3b699347-cb2d-4c9d-96ab-1461fb9c2a25" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_8a993e32-60ad-410f-a2d3-c41a7cbd684d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_3b699347-cb2d-4c9d-96ab-1461fb9c2a25" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_8a993e32-60ad-410f-a2d3-c41a7cbd684d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_20744c66-8491-4773-94e6-eea12e784f38" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_8a993e32-60ad-410f-a2d3-c41a7cbd684d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_20744c66-8491-4773-94e6-eea12e784f38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_f5c2617c-251e-4897-b371-d0c7d923f75a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_8a993e32-60ad-410f-a2d3-c41a7cbd684d" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_f5c2617c-251e-4897-b371-d0c7d923f75a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_cf8518ad-c48b-4c44-935c-f0438f0c98df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_8a993e32-60ad-410f-a2d3-c41a7cbd684d" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_cf8518ad-c48b-4c44-935c-f0438f0c98df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_c4b754f3-569b-4e61-adb8-0f48f4f0d635" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_8a993e32-60ad-410f-a2d3-c41a7cbd684d" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_c4b754f3-569b-4e61-adb8-0f48f4f0d635" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_14aee590-cc70-41cf-8079-162724113a20" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_3b699347-cb2d-4c9d-96ab-1461fb9c2a25" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_14aee590-cc70-41cf-8079-162724113a20" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_dc427098-11bc-4f03-a14b-2d575434b230" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_14aee590-cc70-41cf-8079-162724113a20" xlink:to="loc_us-gaap_FinancialInstrumentAxis_dc427098-11bc-4f03-a14b-2d575434b230" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dc427098-11bc-4f03-a14b-2d575434b230_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_dc427098-11bc-4f03-a14b-2d575434b230" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dc427098-11bc-4f03-a14b-2d575434b230_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b56f4a0b-d7e1-4193-a7da-20ca115205c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_dc427098-11bc-4f03-a14b-2d575434b230" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b56f4a0b-d7e1-4193-a7da-20ca115205c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_e3ce0008-1f08-439a-a22c-cf5158213676" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b56f4a0b-d7e1-4193-a7da-20ca115205c7" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_e3ce0008-1f08-439a-a22c-cf5158213676" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_7e2a56b0-f4c2-4d77-956c-5e11f01c8603" xlink:href="amal-20230930.xsd#amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_e3ce0008-1f08-439a-a22c-cf5158213676" xlink:to="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_7e2a56b0-f4c2-4d77-956c-5e11f01c8603" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember_0bdc48fb-7445-4be0-b9e3-79e75cc20711" xlink:href="amal-20230930.xsd#amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_e3ce0008-1f08-439a-a22c-cf5158213676" xlink:to="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember_0bdc48fb-7445-4be0-b9e3-79e75cc20711" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_a4afb676-dd89-4384-8411-6dfb626a5118" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_e3ce0008-1f08-439a-a22c-cf5158213676" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_a4afb676-dd89-4384-8411-6dfb626a5118" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_d18b7394-98b8-49d6-b383-17d88fd9e3fb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_e3ce0008-1f08-439a-a22c-cf5158213676" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_d18b7394-98b8-49d6-b383-17d88fd9e3fb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b56f4a0b-d7e1-4193-a7da-20ca115205c7" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_bf2b58b7-74ff-4007-a966-a91c1c8cf52c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_bf2b58b7-74ff-4007-a966-a91c1c8cf52c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_cc0387c4-3cb5-42ce-a454-7ed39773770a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:to="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_cc0387c4-3cb5-42ce-a454-7ed39773770a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TrustPreferredSecuritiesMember_5bb7157e-3cb3-412d-bfbf-7ba07c3ecfd4" xlink:href="amal-20230930.xsd#amal_TrustPreferredSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:to="loc_amal_TrustPreferredSecuritiesMember_5bb7157e-3cb3-412d-bfbf-7ba07c3ecfd4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_169f4f47-db01-45fa-b2f0-bf3239fc2e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_169f4f47-db01-45fa-b2f0-bf3239fc2e5f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_fc8022e5-1598-4d74-9dd3-832600c580af" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_ffabb813-f2ca-4372-bfbc-84a63f2e0199" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_fc8022e5-1598-4d74-9dd3-832600c580af" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAmortizedCostandFairValueofHTMSecuritiesDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#INVESTMENTSECURITIESAmortizedCostandFairValueofHTMSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAmortizedCostandFairValueofHTMSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_badb871c-95f5-4b4b-8f48-257767ec96ff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_badb871c-95f5-4b4b-8f48-257767ec96ff" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_67cd6b28-bb25-4436-9c93-a5fb25c79d6a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_67cd6b28-bb25-4436-9c93-a5fb25c79d6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_574dc30c-3bb0-4a6d-9a13-7eb6d9e83e29" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_574dc30c-3bb0-4a6d-9a13-7eb6d9e83e29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_36e3d722-e21c-4f97-b3f7-f87d5ad96d53" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_36e3d722-e21c-4f97-b3f7-f87d5ad96d53" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_1c1d952a-b198-4402-b1c1-83c5aec661b8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_1c1d952a-b198-4402-b1c1-83c5aec661b8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_8da85d6b-c2fb-4f98-8ef2-5ee6dfa5d5d5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_8da85d6b-c2fb-4f98-8ef2-5ee6dfa5d5d5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_549230e0-178f-4d5a-aa88-e1d0407f7d0e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesAbstract_f1643a31-9d1e-49b5-9b5f-b88aad54aa41" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_549230e0-178f-4d5a-aa88-e1d0407f7d0e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_0a9f54e1-49ba-4b0e-aa1f-aa5ceafa5128" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_badb871c-95f5-4b4b-8f48-257767ec96ff" xlink:to="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_0a9f54e1-49ba-4b0e-aa1f-aa5ceafa5128" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_b76fdbd6-cb86-4ee7-a4cf-17409ba20cf8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_0a9f54e1-49ba-4b0e-aa1f-aa5ceafa5128" xlink:to="loc_us-gaap_FinancialInstrumentAxis_b76fdbd6-cb86-4ee7-a4cf-17409ba20cf8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b76fdbd6-cb86-4ee7-a4cf-17409ba20cf8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b76fdbd6-cb86-4ee7-a4cf-17409ba20cf8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b76fdbd6-cb86-4ee7-a4cf-17409ba20cf8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3aa08ce6-acc1-4732-854d-03905fcf1b6c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b76fdbd6-cb86-4ee7-a4cf-17409ba20cf8" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3aa08ce6-acc1-4732-854d-03905fcf1b6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:href="amal-20230930.xsd#amal_CollateralizedTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3aa08ce6-acc1-4732-854d-03905fcf1b6c" xlink:to="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_ce81f07b-9fc6-42f9-8c35-57458001ba5e" xlink:href="amal-20230930.xsd#amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_ce81f07b-9fc6-42f9-8c35-57458001ba5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesMember_2842549c-199f-4f62-819c-16262654b6ab" xlink:href="amal-20230930.xsd#amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesMember_2842549c-199f-4f62-819c-16262654b6ab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCertificatesMember_42786b48-cba9-4cf7-9a26-4520888eeda4" xlink:href="amal-20230930.xsd#amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCertificatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCertificatesMember_42786b48-cba9-4cf7-9a26-4520888eeda4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CommercialTraditionalSecuritiesMember_9c99bf72-c6fe-4b7d-9731-ffe8e7375a92" xlink:href="amal-20230930.xsd#amal_CommercialTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_amal_CommercialTraditionalSecuritiesMember_9c99bf72-c6fe-4b7d-9731-ffe8e7375a92" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ResidentialTraditionalSecuritiesMember_0e1977d6-be0c-4df9-ba7c-aeb085adad83" xlink:href="amal-20230930.xsd#amal_ResidentialTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_amal_ResidentialTraditionalSecuritiesMember_0e1977d6-be0c-4df9-ba7c-aeb085adad83" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_bd0f2271-7547-44dc-8cf7-590e6da3fc8d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_bd0f2271-7547-44dc-8cf7-590e6da3fc8d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalNotesMember_4d2b4299-f31f-439a-a0c1-ecc74df2e8f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MunicipalNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_us-gaap_MunicipalNotesMember_4d2b4299-f31f-439a-a0c1-ecc74df2e8f4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_OtherMiscellaneousDebtObligationsMember_1acf38d2-929a-4c6f-b9ba-de5a91e0714e" xlink:href="amal-20230930.xsd#amal_OtherMiscellaneousDebtObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_7b90db64-ca88-4eb1-94db-1d04ef09ba15" xlink:to="loc_amal_OtherMiscellaneousDebtObligationsMember_1acf38d2-929a-4c6f-b9ba-de5a91e0714e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_f2d200f5-b850-46f2-881a-a61fcd301fa2" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_3aa08ce6-acc1-4732-854d-03905fcf1b6c" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_f2d200f5-b850-46f2-881a-a61fcd301fa2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember_64339a8e-c584-4ea8-8d1d-d286624e437e" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_f2d200f5-b850-46f2-881a-a61fcd301fa2" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember_64339a8e-c584-4ea8-8d1d-d286624e437e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_6cb63762-cd34-496a-9268-a50c6cb5f9ce" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesMember_f2d200f5-b850-46f2-881a-a61fcd301fa2" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_6cb63762-cd34-496a-9268-a50c6cb5f9ce" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESNarrativeDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#INVESTMENTSECURITIESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_22ab89b9-3214-4c90-bd6d-3fb7dd401ff7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_22ab89b9-3214-4c90-bd6d-3fb7dd401ff7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecurities_fca9576b-df45-45ef-b9bd-0254eda7b355" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_us-gaap_HeldToMaturitySecurities_fca9576b-df45-45ef-b9bd-0254eda7b355" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_DebtSecuritiesAvailableForSaleAfterAllowanceForCreditLossFairValueTransferAmount_79b60716-ae91-46fc-bbb0-50804f7e68bc" xlink:href="amal-20230930.xsd#amal_DebtSecuritiesAvailableForSaleAfterAllowanceForCreditLossFairValueTransferAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_amal_DebtSecuritiesAvailableForSaleAfterAllowanceForCreditLossFairValueTransferAmount_79b60716-ae91-46fc-bbb0-50804f7e68bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_DebtSecuritiesAvailableForSaleAmortizedCostAfterAllowanceForCreditLossTransferAmount_5f79effa-5d7f-4624-95a4-224bd2ab1a6f" xlink:href="amal-20230930.xsd#amal_DebtSecuritiesAvailableForSaleAmortizedCostAfterAllowanceForCreditLossTransferAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_amal_DebtSecuritiesAvailableForSaleAmortizedCostAfterAllowanceForCreditLossTransferAmount_5f79effa-5d7f-4624-95a4-224bd2ab1a6f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_OCIHeldToMaturitySecuritiesTransferFromDebtSecuritiesAvailableForSaleUnrealizedGainLossBeforeAdjustmentAndTax_03fc694d-16a2-4160-8fd9-2c69c77eb31c" xlink:href="amal-20230930.xsd#amal_OCIHeldToMaturitySecuritiesTransferFromDebtSecuritiesAvailableForSaleUnrealizedGainLossBeforeAdjustmentAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_amal_OCIHeldToMaturitySecuritiesTransferFromDebtSecuritiesAvailableForSaleUnrealizedGainLossBeforeAdjustmentAndTax_03fc694d-16a2-4160-8fd9-2c69c77eb31c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_20494113-d5ce-4922-a5d3-86a4d9dd32a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_20494113-d5ce-4922-a5d3-86a4d9dd32a3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossWriteoff_ebcf29aa-bb50-4945-a4d8-2125935b3d3a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossWriteoff_ebcf29aa-bb50-4945-a4d8-2125935b3d3a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_86b93203-e3d9-4b19-8090-ee0639d9143d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_86b93203-e3d9-4b19-8090-ee0639d9143d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_f559088f-e4da-43e8-8a31-3ba074b63255" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_0b851a86-fa22-4f3d-b06d-64bc81cbfc79" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_f559088f-e4da-43e8-8a31-3ba074b63255" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_1193ce24-3f25-48e1-a349-e87347dae47a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_f559088f-e4da-43e8-8a31-3ba074b63255" xlink:to="loc_us-gaap_FinancialInstrumentAxis_1193ce24-3f25-48e1-a349-e87347dae47a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1193ce24-3f25-48e1-a349-e87347dae47a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_1193ce24-3f25-48e1-a349-e87347dae47a" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_1193ce24-3f25-48e1-a349-e87347dae47a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7a64dca8-1c74-4b1d-9229-5addffc52ea5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_1193ce24-3f25-48e1-a349-e87347dae47a" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7a64dca8-1c74-4b1d-9229-5addffc52ea5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_6ec4ecd2-e441-4984-b947-33fdaf23552c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7a64dca8-1c74-4b1d-9229-5addffc52ea5" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_6ec4ecd2-e441-4984-b947-33fdaf23552c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusAxis_07d7213f-6e7f-4be6-ae19-d1c34f965ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgedStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_f559088f-e4da-43e8-8a31-3ba074b63255" xlink:to="loc_us-gaap_PledgedStatusAxis_07d7213f-6e7f-4be6-ae19-d1c34f965ec4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusDomain_07d7213f-6e7f-4be6-ae19-d1c34f965ec4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgedStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PledgedStatusAxis_07d7213f-6e7f-4be6-ae19-d1c34f965ec4" xlink:to="loc_us-gaap_PledgedStatusDomain_07d7213f-6e7f-4be6-ae19-d1c34f965ec4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusDomain_3ea04564-0ad6-4670-9027-8b58774659b8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgedStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PledgedStatusAxis_07d7213f-6e7f-4be6-ae19-d1c34f965ec4" xlink:to="loc_us-gaap_PledgedStatusDomain_3ea04564-0ad6-4670-9027-8b58774659b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetPledgedAsCollateralWithoutRightMember_b1f315cf-bbb6-47e6-8e7d-7a24804f777c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetPledgedAsCollateralWithoutRightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PledgedStatusDomain_3ea04564-0ad6-4670-9027-8b58774659b8" xlink:to="loc_us-gaap_AssetPledgedAsCollateralWithoutRightMember_b1f315cf-bbb6-47e6-8e7d-7a24804f777c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeAxis_fea3adcc-b9a7-43ec-8ae3-a1d53c4b437d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgingPurposeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_f559088f-e4da-43e8-8a31-3ba074b63255" xlink:to="loc_us-gaap_PledgingPurposeAxis_fea3adcc-b9a7-43ec-8ae3-a1d53c4b437d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeDomain_fea3adcc-b9a7-43ec-8ae3-a1d53c4b437d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgingPurposeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PledgingPurposeAxis_fea3adcc-b9a7-43ec-8ae3-a1d53c4b437d" xlink:to="loc_us-gaap_PledgingPurposeDomain_fea3adcc-b9a7-43ec-8ae3-a1d53c4b437d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeDomain_9891f7fe-e1e3-4891-a258-a2e226115b00" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgingPurposeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PledgingPurposeAxis_fea3adcc-b9a7-43ec-8ae3-a1d53c4b437d" xlink:to="loc_us-gaap_PledgingPurposeDomain_9891f7fe-e1e3-4891-a258-a2e226115b00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMember_22e6e9a6-be98-4569-86fd-3374fdcce472" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PledgingPurposeDomain_9891f7fe-e1e3-4891-a258-a2e226115b00" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMember_22e6e9a6-be98-4569-86fd-3374fdcce472" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_60e69bb8-4479-45d0-a074-0c5d6ec18c67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_f559088f-e4da-43e8-8a31-3ba074b63255" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_60e69bb8-4479-45d0-a074-0c5d6ec18c67" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_60e69bb8-4479-45d0-a074-0c5d6ec18c67_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_60e69bb8-4479-45d0-a074-0c5d6ec18c67" xlink:to="loc_us-gaap_TypeOfAdoptionMember_60e69bb8-4479-45d0-a074-0c5d6ec18c67_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_900c307a-0b4b-4b19-8ae8-5a3dec235399" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_60e69bb8-4479-45d0-a074-0c5d6ec18c67" xlink:to="loc_us-gaap_TypeOfAdoptionMember_900c307a-0b4b-4b19-8ae8-5a3dec235399" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201613Member_35740ac4-bf02-425b-8626-18edb6b0fc8f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate201613Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_900c307a-0b4b-4b19-8ae8-5a3dec235399" xlink:to="loc_us-gaap_AccountingStandardsUpdate201613Member_35740ac4-bf02-425b-8626-18edb6b0fc8f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAFSandHTMSecuritiesbyContractualMaturityDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#INVESTMENTSECURITIESAFSandHTMSecuritiesbyContractualMaturityDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAFSandHTMSecuritiesbyContractualMaturityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_390493b7-9ecc-45a6-b37a-f91d53aaf791" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_390493b7-9ecc-45a6-b37a-f91d53aaf791" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_19eb41a9-da31-4995-afe0-e4fb396b6314" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_19eb41a9-da31-4995-afe0-e4fb396b6314" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_f0c06381-306e-4b0e-8a31-192b0eb336d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_f0c06381-306e-4b0e-8a31-192b0eb336d6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_88f926b5-529e-4df0-909f-6ddeb938403a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_88f926b5-529e-4df0-909f-6ddeb938403a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_c367f097-80dc-4295-946c-6c92daeb5135" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_c367f097-80dc-4295-946c-6c92daeb5135" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_7e84382c-7928-4e0d-86fa-1785e065b785" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_21edcd00-120c-4cba-992d-c7dca1eb5902" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss_7e84382c-7928-4e0d-86fa-1785e065b785" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_390493b7-9ecc-45a6-b37a-f91d53aaf791" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_613a8a6d-ce19-4beb-9899-509055eb891e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_613a8a6d-ce19-4beb-9899-509055eb891e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_fb773c18-bba0-4b43-b355-f4be6e1891c4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_fb773c18-bba0-4b43-b355-f4be6e1891c4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_dc1e4bad-da13-4f1d-8638-3410a35b5c10" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_dc1e4bad-da13-4f1d-8638-3410a35b5c10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_2e9440fd-97e6-4082-943f-27a9efb3cc58" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_2e9440fd-97e6-4082-943f-27a9efb3cc58" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_79d1358f-0261-450f-b01f-ea3563a8297c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAbstract_87753db7-8856-49ca-a905-c0de7f1bf565" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_79d1358f-0261-450f-b01f-ea3563a8297c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28892b27-4667-4f5b-9aeb-0f23a5623bf0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_390493b7-9ecc-45a6-b37a-f91d53aaf791" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28892b27-4667-4f5b-9aeb-0f23a5623bf0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_db31ce1a-02f7-4af5-b75d-cb2b794fa72d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_28892b27-4667-4f5b-9aeb-0f23a5623bf0" xlink:to="loc_us-gaap_FinancialInstrumentAxis_db31ce1a-02f7-4af5-b75d-cb2b794fa72d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_db31ce1a-02f7-4af5-b75d-cb2b794fa72d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_db31ce1a-02f7-4af5-b75d-cb2b794fa72d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_db31ce1a-02f7-4af5-b75d-cb2b794fa72d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_53ca0b45-1942-4316-a189-1ebcb296964f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_db31ce1a-02f7-4af5-b75d-cb2b794fa72d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_53ca0b45-1942-4316-a189-1ebcb296964f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_8c64fc86-cd75-4e22-9f63-41989daf92af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_53ca0b45-1942-4316-a189-1ebcb296964f" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_8c64fc86-cd75-4e22-9f63-41989daf92af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_52f62dc8-9765-49e0-af9d-214a1ab135ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_52f62dc8-9765-49e0-af9d-214a1ab135ef" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_af940479-876e-45be-b811-facf944a2cce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_af940479-876e-45be-b811-facf944a2cce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount_99073855-e008-4a65-b7de-3d58fb0fed35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount_99073855-e008-4a65-b7de-3d58fb0fed35" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount_a6bb8f26-89d4-4c17-8a43-bba857d66793" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount_a6bb8f26-89d4-4c17-8a43-bba857d66793" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount_e95a7380-c15d-403e-bf61-980b73e277ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount_e95a7380-c15d-403e-bf61-980b73e277ac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_9e924691-001e-432e-8ca4-79dfe3a0946f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasisAbstract_27780344-08cc-449d-b4ba-3f6dd48523b3" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss_9e924691-001e-432e-8ca4-79dfe3a0946f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_52f62dc8-9765-49e0-af9d-214a1ab135ef" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_bc13a814-f333-4485-80c2-c174c71c97b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_bc13a814-f333-4485-80c2-c174c71c97b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_bf4fde51-2c6c-4ad0-b338-f586086557e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_bf4fde51-2c6c-4ad0-b338-f586086557e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_450f7d39-a5c2-457c-86f4-1cd47c8f11d1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_450f7d39-a5c2-457c-86f4-1cd47c8f11d1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_a0207665-2a18-449f-be29-086afde5f48d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_a0207665-2a18-449f-be29-086afde5f48d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_9b46e8b7-76f0-43e2-9b2a-2dd84e0320fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_8d9a9981-3e57-40a8-86eb-3b5153a4fc7a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_9b46e8b7-76f0-43e2-9b2a-2dd84e0320fe" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_c2341603-3bc2-43df-bf71-d9250635ad37" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems_52f62dc8-9765-49e0-af9d-214a1ab135ef" xlink:to="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_c2341603-3bc2-43df-bf71-d9250635ad37" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_c5211227-fbc5-4488-8aaf-5ee9cd1d138a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_c2341603-3bc2-43df-bf71-d9250635ad37" xlink:to="loc_us-gaap_FinancialInstrumentAxis_c5211227-fbc5-4488-8aaf-5ee9cd1d138a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c5211227-fbc5-4488-8aaf-5ee9cd1d138a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_a3717920-cb4b-489e-94c5-09d8115895fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_cd9aa901-2b45-40f5-aac4-0d6b08e7ddcb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherDebtSecuritiesMember"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESScheduleofUnrealizedLossesonAvailableforSaleSecuritiesandHeldtoMaturitySecuritiesDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#INVESTMENTSECURITIESScheduleofUnrealizedLossesonAvailableforSaleSecuritiesandHeldtoMaturitySecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESScheduleofUnrealizedLossesonAvailableforSaleSecuritiesandHeldtoMaturitySecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_ae39d637-ff9d-43f2-8aea-5d5e3de42c41" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_ae39d637-ff9d-43f2-8aea-5d5e3de42c41" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_c1687a33-7360-4654-a819-ab7c22fe98a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_c1687a33-7360-4654-a819-ab7c22fe98a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_680e5423-f5d3-4da8-894a-65b2088162ee" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_680e5423-f5d3-4da8-894a-65b2088162ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_22f27f3e-6a7d-43db-873a-4ade84db3588" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_22f27f3e-6a7d-43db-873a-4ade84db3588" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_24b8a667-7bf4-4728-8820-8a31a8588959" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_24b8a667-7bf4-4728-8820-8a31a8588959" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_5692d8b4-d0d7-40a6-9e87-8b6ac982c70b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_5692d8b4-d0d7-40a6-9e87-8b6ac982c70b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_d6d1a02d-dba5-4df9-b91f-4a3d818675e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_a3052066-8f08-4a01-92df-c4830177e025" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_d6d1a02d-dba5-4df9-b91f-4a3d818675e5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_ae39d637-ff9d-43f2-8aea-5d5e3de42c41" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_376cfe7b-d3f2-4a29-968b-a0d60a2e4701" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_376cfe7b-d3f2-4a29-968b-a0d60a2e4701" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_ce08080c-b638-49d9-bcf1-374b74b4fde9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_ce08080c-b638-49d9-bcf1-374b74b4fde9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_93feba24-8843-4b9e-8cf8-68ad1c62ef24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_93feba24-8843-4b9e-8cf8-68ad1c62ef24" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_797d453f-e7ac-40cc-a3df-4e5bd0a4703f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_797d453f-e7ac-40cc-a3df-4e5bd0a4703f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue_3f11d754-4032-430e-9b11-475754634453" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue_3f11d754-4032-430e-9b11-475754634453" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_a07c13aa-5c44-47de-b07e-20b46ffaf3d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract_c08a03aa-8cbc-43c2-9772-2e348a29c3fe" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_a07c13aa-5c44-47de-b07e-20b46ffaf3d9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3d9e43e1-ec3f-4d6a-a5b1-62c7785b52e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_ae39d637-ff9d-43f2-8aea-5d5e3de42c41" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3d9e43e1-ec3f-4d6a-a5b1-62c7785b52e1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_4a0c3023-24e2-4f9f-b906-3f43dd524c02" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3d9e43e1-ec3f-4d6a-a5b1-62c7785b52e1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_4a0c3023-24e2-4f9f-b906-3f43dd524c02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4a0c3023-24e2-4f9f-b906-3f43dd524c02_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_4a0c3023-24e2-4f9f-b906-3f43dd524c02" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_4a0c3023-24e2-4f9f-b906-3f43dd524c02_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e97c3d55-60ae-4c92-b37d-61c434fa171e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_4a0c3023-24e2-4f9f-b906-3f43dd524c02" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e97c3d55-60ae-4c92-b37d-61c434fa171e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_cdfb56d8-d5c7-43c8-9a6d-4d472e126357" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e97c3d55-60ae-4c92-b37d-61c434fa171e" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_cdfb56d8-d5c7-43c8-9a6d-4d472e126357" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_ac052dd5-0be2-4abb-8285-7128cd6efd89" xlink:href="amal-20230930.xsd#amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_cdfb56d8-d5c7-43c8-9a6d-4d472e126357" xlink:to="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_ac052dd5-0be2-4abb-8285-7128cd6efd89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember_bc2898fc-5553-4077-8560-fef1ee37a0ad" xlink:href="amal-20230930.xsd#amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_cdfb56d8-d5c7-43c8-9a6d-4d472e126357" xlink:to="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember_bc2898fc-5553-4077-8560-fef1ee37a0ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_90734bf6-943d-49a6-a592-7e1c995f74df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_cdfb56d8-d5c7-43c8-9a6d-4d472e126357" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_90734bf6-943d-49a6-a592-7e1c995f74df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_dae6f795-ae5e-4435-9384-52d4041bb2ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_cdfb56d8-d5c7-43c8-9a6d-4d472e126357" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_dae6f795-ae5e-4435-9384-52d4041bb2ac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e97c3d55-60ae-4c92-b37d-61c434fa171e" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_6afca4e3-6651-428c-bb81-e02087b80b2a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_6afca4e3-6651-428c-bb81-e02087b80b2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_c8ae0c30-b037-4f97-8bac-d405ffd315ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:to="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_c8ae0c30-b037-4f97-8bac-d405ffd315ac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TrustPreferredSecuritiesMember_7e12ce00-0be3-4205-ab46-3bd8c675f08f" xlink:href="amal-20230930.xsd#amal_TrustPreferredSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:to="loc_amal_TrustPreferredSecuritiesMember_7e12ce00-0be3-4205-ab46-3bd8c675f08f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_6af8d65f-bd9e-4164-bf6f-2271d5ad9542" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_6af8d65f-bd9e-4164-bf6f-2271d5ad9542" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_e42d72e9-0390-4dff-80b1-b3245d3bdd9e" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_64b0f5f6-3644-45f1-ae10-69ea5ce4ea00" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_e42d72e9-0390-4dff-80b1-b3245d3bdd9e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:href="amal-20230930.xsd#amal_CollateralizedTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e97c3d55-60ae-4c92-b37d-61c434fa171e" xlink:to="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCollateralizedMortgageObligationsMember_bb8ccc1c-0f92-461b-a921-4930dcf670fa" xlink:href="amal-20230930.xsd#amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:to="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCollateralizedMortgageObligationsMember_bb8ccc1c-0f92-461b-a921-4930dcf670fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesMember_304ae002-3153-4a76-b098-1b3f68de4d57" xlink:href="amal-20230930.xsd#amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:to="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesMember_304ae002-3153-4a76-b098-1b3f68de4d57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCertificatesMember_4eb43e22-bf04-4b1e-8c28-b3d9a0c8d78a" xlink:href="amal-20230930.xsd#amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCertificatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:to="loc_amal_TraditionalSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCertificatesMember_4eb43e22-bf04-4b1e-8c28-b3d9a0c8d78a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CommercialTraditionalSecuritiesMember_ed206717-4225-46a2-a4a1-4667322c21cb" xlink:href="amal-20230930.xsd#amal_CommercialTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:to="loc_amal_CommercialTraditionalSecuritiesMember_ed206717-4225-46a2-a4a1-4667322c21cb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ResidentialTraditionalSecuritiesMember_7d553b1c-03f5-416b-8826-487fe1ce4fc6" xlink:href="amal-20230930.xsd#amal_ResidentialTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:to="loc_amal_ResidentialTraditionalSecuritiesMember_7d553b1c-03f5-416b-8826-487fe1ce4fc6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_11c13fb4-5a29-43f2-8a24-5c5aa368602c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalNotesMember_72989978-24b8-446e-881b-031916e0808b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MunicipalNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_CollateralizedTraditionalSecuritiesMember_f62fa57d-759d-4626-a987-4ace336ea217" xlink:to="loc_us-gaap_MunicipalNotesMember_72989978-24b8-446e-881b-031916e0808b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember_5ac2eed0-5709-45d7-a735-9d27e0a992b5" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e97c3d55-60ae-4c92-b37d-61c434fa171e" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember_5ac2eed0-5709-45d7-a735-9d27e0a992b5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_77d493d7-0748-490d-b9d6-8e7dd3a2f04b" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAllowanceforCreditLossesDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#INVESTMENTSECURITIESAllowanceforCreditLossesDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/INVESTMENTSECURITIESAllowanceforCreditLossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_9444d28d-5a1e-4689-a049-63cb89679856" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward_140c3c4d-3dfe-4a9a-a7ae-dac277d6a128" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_9444d28d-5a1e-4689-a049-63cb89679856" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward_140c3c4d-3dfe-4a9a-a7ae-dac277d6a128" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_dde1380b-915e-4d8c-b8fb-39e59ac04ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward_140c3c4d-3dfe-4a9a-a7ae-dac277d6a128" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_dde1380b-915e-4d8c-b8fb-39e59ac04ac1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal_64719c3a-7396-4f27-86db-7d9d09f875bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward_140c3c4d-3dfe-4a9a-a7ae-dac277d6a128" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal_64719c3a-7396-4f27-86db-7d9d09f875bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossWriteoff_f92cd231-5925-43d9-a11d-7e9910c9a0db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward_140c3c4d-3dfe-4a9a-a7ae-dac277d6a128" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossWriteoff_f92cd231-5925-43d9-a11d-7e9910c9a0db" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRecovery_3164b22c-61b7-44ea-b60e-fb31a7356504" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRollForward_140c3c4d-3dfe-4a9a-a7ae-dac277d6a128" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAllowanceForCreditLossRecovery_3164b22c-61b7-44ea-b60e-fb31a7356504" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest_9454e84a-18d0-43b0-be74-520dc5a122aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_fcfae5c0-6789-4ea8-82eb-37d14390b79a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_9444d28d-5a1e-4689-a049-63cb89679856" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_fcfae5c0-6789-4ea8-82eb-37d14390b79a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_01c87781-6911-48ad-b9bb-cfab587d5fcf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_fcfae5c0-6789-4ea8-82eb-37d14390b79a" xlink:to="loc_us-gaap_FinancialInstrumentAxis_01c87781-6911-48ad-b9bb-cfab587d5fcf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_01c87781-6911-48ad-b9bb-cfab587d5fcf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_01c87781-6911-48ad-b9bb-cfab587d5fcf" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_01c87781-6911-48ad-b9bb-cfab587d5fcf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7d8754ec-0b46-4311-9a59-95ca06de2822" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_01c87781-6911-48ad-b9bb-cfab587d5fcf" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7d8754ec-0b46-4311-9a59-95ca06de2822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_CommercialTraditionalSecuritiesMember_c92e38aa-fa33-480f-b2d5-21892730422f" xlink:href="amal-20230930.xsd#amal_CommercialTraditionalSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7d8754ec-0b46-4311-9a59-95ca06de2822" xlink:to="loc_amal_CommercialTraditionalSecuritiesMember_c92e38aa-fa33-480f-b2d5-21892730422f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember_287dbb73-10ab-4fa5-8f74-b00ce52c6e12" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7d8754ec-0b46-4311-9a59-95ca06de2822" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesCommercialMember_287dbb73-10ab-4fa5-8f74-b00ce52c6e12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_541cd343-c09e-4878-b0ae-f7204be0494c" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_7d8754ec-0b46-4311-9a59-95ca06de2822" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_541cd343-c09e-4878-b0ae-f7204be0494c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_417f3733-6673-4c53-b449-ceff591b73a1" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_fcfae5c0-6789-4ea8-82eb-37d14390b79a" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_417f3733-6673-4c53-b449-ceff591b73a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_417f3733-6673-4c53-b449-ceff591b73a1_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_417f3733-6673-4c53-b449-ceff591b73a1" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_417f3733-6673-4c53-b449-ceff591b73a1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f69eab64-465c-4228-8071-55859b4da050" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_417f3733-6673-4c53-b449-ceff591b73a1" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f69eab64-465c-4228-8071-55859b4da050" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_fcf37dee-3258-482d-bab3-7c2a1f889ad8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f69eab64-465c-4228-8071-55859b4da050" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_fcf37dee-3258-482d-bab3-7c2a1f889ad8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofLoansReceivableDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETScheduleofLoansReceivableDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofLoansReceivableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_0b2cd3bf-d0c9-41d0-85ab-20e1a380b32a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:to="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_0b2cd3bf-d0c9-41d0-85ab-20e1a380b32a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableUnamortizedLoanCommitmentOriginationFeeAndPremiumDiscount_69ec720e-398a-4b91-8ed3-ca48c1beeaf9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableUnamortizedLoanCommitmentOriginationFeeAndPremiumDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:to="loc_us-gaap_FinancingReceivableUnamortizedLoanCommitmentOriginationFeeAndPremiumDiscount_69ec720e-398a-4b91-8ed3-ca48c1beeaf9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_a6de5a18-ae3b-4e26-8dbd-832ace9810cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_a6de5a18-ae3b-4e26-8dbd-832ace9810cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_93037a2c-969f-4aee-b02f-b2468cb22fb3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_93037a2c-969f-4aee-b02f-b2468cb22fb3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_95a0bfc5-f40d-41f8-b425-1071df34b2bc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_95a0bfc5-f40d-41f8-b425-1071df34b2bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9e5d6e75-07ba-4649-abd7-c67830315d12" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_c23a3aa2-1697-472a-a4bb-e83d7dc06ec4" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9e5d6e75-07ba-4649-abd7-c67830315d12" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_e0951f3a-02c2-47e2-98a7-50c8ed03b6ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9e5d6e75-07ba-4649-abd7-c67830315d12" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_e0951f3a-02c2-47e2-98a7-50c8ed03b6ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e0951f3a-02c2-47e2-98a7-50c8ed03b6ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_e0951f3a-02c2-47e2-98a7-50c8ed03b6ca" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e0951f3a-02c2-47e2-98a7-50c8ed03b6ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fc824c25-d4f6-43f9-aeee-2d1c99caee47" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_e0951f3a-02c2-47e2-98a7-50c8ed03b6ca" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fc824c25-d4f6-43f9-aeee-2d1c99caee47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_01d5ae34-ec62-4709-913f-b4f6ba133ad5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fc824c25-d4f6-43f9-aeee-2d1c99caee47" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_01d5ae34-ec62-4709-913f-b4f6ba133ad5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_c189cd85-b307-41b1-ba08-5eb190b2952f" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fc824c25-d4f6-43f9-aeee-2d1c99caee47" xlink:to="loc_amal_RetailPortfolioSegmentMember_c189cd85-b307-41b1-ba08-5eb190b2952f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_afc36e39-70e7-4da4-9691-8b269d91cad0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9e5d6e75-07ba-4649-abd7-c67830315d12" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_afc36e39-70e7-4da4-9691-8b269d91cad0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_afc36e39-70e7-4da4-9691-8b269d91cad0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_afc36e39-70e7-4da4-9691-8b269d91cad0" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_afc36e39-70e7-4da4-9691-8b269d91cad0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_afc36e39-70e7-4da4-9691-8b269d91cad0" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_dc31c4e9-b1d0-460c-a6b8-f9ad26db822b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_dc31c4e9-b1d0-460c-a6b8-f9ad26db822b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_277950aa-9852-4f39-96b0-e88a84386d1c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_srt_MultifamilyMember_277950aa-9852-4f39-96b0-e88a84386d1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_b3adb0c6-f5b3-4f6e-914e-e1036e6412c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_us-gaap_CommercialRealEstateMember_b3adb0c6-f5b3-4f6e-914e-e1036e6412c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_ff7be252-f7a8-48b9-be96-0e8f70796395" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_us-gaap_ConstructionLoansMember_ff7be252-f7a8-48b9-be96-0e8f70796395" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_9a9525ff-dc33-4ee3-8bd5-6355b9f1fce9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_us-gaap_ResidentialRealEstateMember_9a9525ff-dc33-4ee3-8bd5-6355b9f1fce9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerSolarMember_e234f4e0-cc7d-4d1e-9142-9d1d1a8e8a85" xlink:href="amal-20230930.xsd#amal_ConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_amal_ConsumerSolarMember_e234f4e0-cc7d-4d1e-9142-9d1d1a8e8a85" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherMember_4ce4bd0b-a209-43ef-8dda-dd7c7e2198ac" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_90db0b4a-58e4-492c-96cc-91fdde5eef38" xlink:to="loc_amal_ConsumerAndOtherMember_4ce4bd0b-a209-43ef-8dda-dd7c7e2198ac" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofQualityofBanksLoansDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETScheduleofQualityofBanksLoansDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofQualityofBanksLoansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_5136c093-e69c-47c3-bb6d-e922fdecf73d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_95bd7885-fec8-4a6c-95a5-36cea01d7d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_5136c093-e69c-47c3-bb6d-e922fdecf73d" xlink:to="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_95bd7885-fec8-4a6c-95a5-36cea01d7d3e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_ef810507-b8b9-419b-9eac-a253b6a3a3a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_5136c093-e69c-47c3-bb6d-e922fdecf73d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_ef810507-b8b9-419b-9eac-a253b6a3a3a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruing_a14977a2-1863-4d94-b40f-6c951782f3e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_5136c093-e69c-47c3-bb6d-e922fdecf73d" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruing_a14977a2-1863-4d94-b40f-6c951782f3e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_6af69f0d-bb19-431e-b329-df9e1217e43e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_5136c093-e69c-47c3-bb6d-e922fdecf73d" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_6af69f0d-bb19-431e-b329-df9e1217e43e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5e127ad2-dcc8-4885-ab00-92aae68792a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_6af69f0d-bb19-431e-b329-df9e1217e43e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5e127ad2-dcc8-4885-ab00-92aae68792a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5e127ad2-dcc8-4885-ab00-92aae68792a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5e127ad2-dcc8-4885-ab00-92aae68792a8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5e127ad2-dcc8-4885-ab00-92aae68792a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a4070153-312f-484f-9d90-7fb6e9cc5a28" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_5e127ad2-dcc8-4885-ab00-92aae68792a8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a4070153-312f-484f-9d90-7fb6e9cc5a28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_d388b647-595f-48d9-8d5f-dd424dbe8f95" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a4070153-312f-484f-9d90-7fb6e9cc5a28" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_d388b647-595f-48d9-8d5f-dd424dbe8f95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_9c1211aa-f48a-4144-8f05-b3534af39cae" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a4070153-312f-484f-9d90-7fb6e9cc5a28" xlink:to="loc_amal_RetailPortfolioSegmentMember_9c1211aa-f48a-4144-8f05-b3534af39cae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9dd0ca8e-dfa6-49b4-b595-c1131d21405d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_6af69f0d-bb19-431e-b329-df9e1217e43e" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9dd0ca8e-dfa6-49b4-b595-c1131d21405d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9dd0ca8e-dfa6-49b4-b595-c1131d21405d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9dd0ca8e-dfa6-49b4-b595-c1131d21405d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_9dd0ca8e-dfa6-49b4-b595-c1131d21405d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_9dd0ca8e-dfa6-49b4-b595-c1131d21405d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_e5e0d043-2de8-4013-a282-f7fc0006405f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_e5e0d043-2de8-4013-a282-f7fc0006405f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_25919f91-e8f5-422b-97c7-5c19fe514bb3" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_srt_MultifamilyMember_25919f91-e8f5-422b-97c7-5c19fe514bb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_2c5d4997-0431-47c5-838e-7652a6ba035c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_us-gaap_CommercialRealEstateMember_2c5d4997-0431-47c5-838e-7652a6ba035c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_b8507061-9f36-40ad-a6e9-d8e740307fca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_us-gaap_ConstructionLoansMember_b8507061-9f36-40ad-a6e9-d8e740307fca" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_a12bf7eb-99de-4b82-861b-d2e32a45d6a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_us-gaap_ResidentialRealEstateMember_a12bf7eb-99de-4b82-861b-d2e32a45d6a1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerSolarMember_b577424a-9520-4a16-89bb-4d714ab95cb0" xlink:href="amal-20230930.xsd#amal_ConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_amal_ConsumerSolarMember_b577424a-9520-4a16-89bb-4d714ab95cb0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherMember_0bf5b242-b62c-4092-8be3-e37a7a835db9" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_f4b76afc-4e4d-4b4c-bb21-2f8ecfbe820e" xlink:to="loc_amal_ConsumerAndOtherMember_0bf5b242-b62c-4092-8be3-e37a7a835db9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_a9cea8d1-c1d6-4f31-b14f-ad79a96c633b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_6af69f0d-bb19-431e-b329-df9e1217e43e" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_a9cea8d1-c1d6-4f31-b14f-ad79a96c633b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_a9cea8d1-c1d6-4f31-b14f-ad79a96c633b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_a9cea8d1-c1d6-4f31-b14f-ad79a96c633b" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_a9cea8d1-c1d6-4f31-b14f-ad79a96c633b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_4d1da908-abe0-4b12-b72a-827a72de5dc5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_a9cea8d1-c1d6-4f31-b14f-ad79a96c633b" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_4d1da908-abe0-4b12-b72a-827a72de5dc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_FinancialAsset30To89DaysPastDueMember_5f9e338f-c4c2-4d7b-b889-2e13b6bbdf02" xlink:href="amal-20230930.xsd#amal_FinancialAsset30To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_4d1da908-abe0-4b12-b72a-827a72de5dc5" xlink:to="loc_amal_FinancialAsset30To89DaysPastDueMember_5f9e338f-c4c2-4d7b-b889-2e13b6bbdf02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetPastDueMember_e8e9278c-dc4a-4318-b02a-f3d4ac8783b7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialAssetPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_4d1da908-abe0-4b12-b72a-827a72de5dc5" xlink:to="loc_us-gaap_FinancialAssetPastDueMember_e8e9278c-dc4a-4318-b02a-f3d4ac8783b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_6bd63081-283f-40a2-b151-cb5049970fc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_4d1da908-abe0-4b12-b72a-827a72de5dc5" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_6bd63081-283f-40a2-b151-cb5049970fc2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETLoanModificationsDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETLoanModificationsDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETLoanModificationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_3f1e3280-5c36-40e0-86a7-44231c5e3868" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod_3e847c2b-d250-452c-abfc-e15198ab9997" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_3f1e3280-5c36-40e0-86a7-44231c5e3868" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod_3e847c2b-d250-452c-abfc-e15198ab9997" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent_b3059e88-ee1a-45b6-bdd6-455976920b90" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_3f1e3280-5c36-40e0-86a7-44231c5e3868" xlink:to="loc_us-gaap_FinancingReceivableModificationToTotalFinancingReceivablesExcludingAccruedInterestPercent_b3059e88-ee1a-45b6-bdd6-455976920b90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_795e29e9-4821-4539-a084-7765d54489f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_3f1e3280-5c36-40e0-86a7-44231c5e3868" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_795e29e9-4821-4539-a084-7765d54489f8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6d486ba7-48ff-4bbf-b99b-94d1100e2900" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_795e29e9-4821-4539-a084-7765d54489f8" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6d486ba7-48ff-4bbf-b99b-94d1100e2900" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6d486ba7-48ff-4bbf-b99b-94d1100e2900_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6d486ba7-48ff-4bbf-b99b-94d1100e2900" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_6d486ba7-48ff-4bbf-b99b-94d1100e2900_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_2a53ebd1-c379-46ff-8ecb-c648d7d47fcc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_6d486ba7-48ff-4bbf-b99b-94d1100e2900" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_2a53ebd1-c379-46ff-8ecb-c648d7d47fcc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_0997c2fd-af66-4fe9-a99a-584dd8b71a85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_2a53ebd1-c379-46ff-8ecb-c648d7d47fcc" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_0997c2fd-af66-4fe9-a99a-584dd8b71a85" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_2440a4a6-fbe0-4189-8f8c-d932ebf229ce" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_2a53ebd1-c379-46ff-8ecb-c648d7d47fcc" xlink:to="loc_srt_MultifamilyMember_2440a4a6-fbe0-4189-8f8c-d932ebf229ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_c2964127-fece-4a21-bf0a-ba4af55afc56" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_2a53ebd1-c379-46ff-8ecb-c648d7d47fcc" xlink:to="loc_us-gaap_CommercialRealEstateMember_c2964127-fece-4a21-bf0a-ba4af55afc56" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_f8bc6848-af7e-4fcb-9d56-b9a717087c7e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_2a53ebd1-c379-46ff-8ecb-c648d7d47fcc" xlink:to="loc_us-gaap_ConstructionLoansMember_f8bc6848-af7e-4fcb-9d56-b9a717087c7e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_a2f1494c-2715-49b4-847b-0f305a6e05f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_795e29e9-4821-4539-a084-7765d54489f8" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_a2f1494c-2715-49b4-847b-0f305a6e05f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_a2f1494c-2715-49b4-847b-0f305a6e05f8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_a2f1494c-2715-49b4-847b-0f305a6e05f8" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_a2f1494c-2715-49b4-847b-0f305a6e05f8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_a142b2d6-c944-4c91-8a05-a4f72e351e9d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_a2f1494c-2715-49b4-847b-0f305a6e05f8" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_a142b2d6-c944-4c91-8a05-a4f72e351e9d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_ba88c831-ace2-4c28-bc92-3a72e7541080" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_a142b2d6-c944-4c91-8a05-a4f72e351e9d" xlink:to="loc_us-gaap_ExtendedMaturityMember_ba88c831-ace2-4c28-bc92-3a72e7541080" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ExtendedMaturityAndPaymentDeferralMember_ef45029b-084a-4a17-b974-27e3be0ea042" xlink:href="amal-20230930.xsd#amal_ExtendedMaturityAndPaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_a142b2d6-c944-4c91-8a05-a4f72e351e9d" xlink:to="loc_amal_ExtendedMaturityAndPaymentDeferralMember_ef45029b-084a-4a17-b974-27e3be0ea042" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETTermExtensionDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETTermExtensionDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETTermExtensionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_69f66907-eea3-43dc-a255-15ba44543ffa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification_82460aea-d0a5-489f-9925-230ee7ff4c68" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_69f66907-eea3-43dc-a255-15ba44543ffa" xlink:to="loc_us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification_82460aea-d0a5-489f-9925-230ee7ff4c68" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModificationAndPaymentDeferral_b07d20c9-01c9-41ac-b15a-e236bc3c7314" xlink:href="amal-20230930.xsd#amal_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModificationAndPaymentDeferral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_69f66907-eea3-43dc-a255-15ba44543ffa" xlink:to="loc_amal_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModificationAndPaymentDeferral_b07d20c9-01c9-41ac-b15a-e236bc3c7314" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_a28ec500-0a15-4852-9341-f27cfa3f3f5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_69f66907-eea3-43dc-a255-15ba44543ffa" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_a28ec500-0a15-4852-9341-f27cfa3f3f5e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6dec8fc1-5bd2-4bad-b2e7-24ee0c892676" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_a28ec500-0a15-4852-9341-f27cfa3f3f5e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6dec8fc1-5bd2-4bad-b2e7-24ee0c892676" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6dec8fc1-5bd2-4bad-b2e7-24ee0c892676_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6dec8fc1-5bd2-4bad-b2e7-24ee0c892676" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6dec8fc1-5bd2-4bad-b2e7-24ee0c892676_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_61a34b48-54a9-4c13-9a5f-e3b4e3394947" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_6dec8fc1-5bd2-4bad-b2e7-24ee0c892676" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_61a34b48-54a9-4c13-9a5f-e3b4e3394947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_ee3b723b-7622-4305-b099-4f448052f463" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_61a34b48-54a9-4c13-9a5f-e3b4e3394947" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_ee3b723b-7622-4305-b099-4f448052f463" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_52d91bf7-bda4-4e37-8034-38cb311dac4d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_a28ec500-0a15-4852-9341-f27cfa3f3f5e" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_52d91bf7-bda4-4e37-8034-38cb311dac4d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_52d91bf7-bda4-4e37-8034-38cb311dac4d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_52d91bf7-bda4-4e37-8034-38cb311dac4d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_52d91bf7-bda4-4e37-8034-38cb311dac4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_ac004772-912d-47f8-ba5a-ee678b3d0422" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_52d91bf7-bda4-4e37-8034-38cb311dac4d" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_ac004772-912d-47f8-ba5a-ee678b3d0422" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_b4efe419-b905-42ab-86cf-9f7964f512bb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_ac004772-912d-47f8-ba5a-ee678b3d0422" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_b4efe419-b905-42ab-86cf-9f7964f512bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_f006cace-ffde-4224-a392-76f92a6b5811" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_ac004772-912d-47f8-ba5a-ee678b3d0422" xlink:to="loc_srt_MultifamilyMember_f006cace-ffde-4224-a392-76f92a6b5811" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_f64dc8af-4572-4d31-92e2-f829db6187e7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_ac004772-912d-47f8-ba5a-ee678b3d0422" xlink:to="loc_us-gaap_CommercialRealEstateMember_f64dc8af-4572-4d31-92e2-f829db6187e7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_b6364537-a38c-4b08-bf28-b474a700584a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_ac004772-912d-47f8-ba5a-ee678b3d0422" xlink:to="loc_us-gaap_ConstructionLoansMember_b6364537-a38c-4b08-bf28-b474a700584a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETNarrativeDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_e5dd29d8-8df7-4d4b-88a3-c4615aa47fac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_58e09430-87a4-4c77-a6e0-b12031b47bbe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_e5dd29d8-8df7-4d4b-88a3-c4615aa47fac" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_58e09430-87a4-4c77-a6e0-b12031b47bbe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_1e1599e4-260d-455e-ac83-a5316b1036fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_e5dd29d8-8df7-4d4b-88a3-c4615aa47fac" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_1e1599e4-260d-455e-ac83-a5316b1036fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansAndLeasesReceivableRelatedParties_e5fb75c9-6015-47d1-9300-bc6a07b5952f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoansAndLeasesReceivableRelatedParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_e5dd29d8-8df7-4d4b-88a3-c4615aa47fac" xlink:to="loc_us-gaap_LoansAndLeasesReceivableRelatedParties_e5fb75c9-6015-47d1-9300-bc6a07b5952f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c2742d82-4507-4ad8-b96e-4fd306ee0c9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_e5dd29d8-8df7-4d4b-88a3-c4615aa47fac" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c2742d82-4507-4ad8-b96e-4fd306ee0c9e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusAxis_04611dae-7aa0-401a-b991-7a7f7d9b3680" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgedStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c2742d82-4507-4ad8-b96e-4fd306ee0c9e" xlink:to="loc_us-gaap_PledgedStatusAxis_04611dae-7aa0-401a-b991-7a7f7d9b3680" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusDomain_04611dae-7aa0-401a-b991-7a7f7d9b3680_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgedStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PledgedStatusAxis_04611dae-7aa0-401a-b991-7a7f7d9b3680" xlink:to="loc_us-gaap_PledgedStatusDomain_04611dae-7aa0-401a-b991-7a7f7d9b3680_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusDomain_f8a2a3ab-1afd-46f9-8fa7-dc62f637ef49" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgedStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PledgedStatusAxis_04611dae-7aa0-401a-b991-7a7f7d9b3680" xlink:to="loc_us-gaap_PledgedStatusDomain_f8a2a3ab-1afd-46f9-8fa7-dc62f637ef49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetPledgedAsCollateralWithoutRightMember_77edad63-0f33-44ff-bc9b-225cab984b99" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetPledgedAsCollateralWithoutRightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PledgedStatusDomain_f8a2a3ab-1afd-46f9-8fa7-dc62f637ef49" xlink:to="loc_us-gaap_AssetPledgedAsCollateralWithoutRightMember_77edad63-0f33-44ff-bc9b-225cab984b99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeAxis_3c165c6e-34cc-417c-9eff-74c2b0c45e06" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgingPurposeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c2742d82-4507-4ad8-b96e-4fd306ee0c9e" xlink:to="loc_us-gaap_PledgingPurposeAxis_3c165c6e-34cc-417c-9eff-74c2b0c45e06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeDomain_3c165c6e-34cc-417c-9eff-74c2b0c45e06_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgingPurposeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PledgingPurposeAxis_3c165c6e-34cc-417c-9eff-74c2b0c45e06" xlink:to="loc_us-gaap_PledgingPurposeDomain_3c165c6e-34cc-417c-9eff-74c2b0c45e06_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeDomain_419b82c5-94b4-47e0-a444-0e31a11f97bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PledgingPurposeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PledgingPurposeAxis_3c165c6e-34cc-417c-9eff-74c2b0c45e06" xlink:to="loc_us-gaap_PledgingPurposeDomain_419b82c5-94b4-47e0-a444-0e31a11f97bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesMember_c2bc9296-2029-433e-948a-2b6e642ecefc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankAdvancesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PledgingPurposeDomain_419b82c5-94b4-47e0-a444-0e31a11f97bd" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesMember_c2bc9296-2029-433e-948a-2b6e642ecefc" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETQualityIndicatorDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETQualityIndicatorDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETQualityIndicatorDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_c467f135-e7d9-4e10-b6df-17b2c959aaef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_c467f135-e7d9-4e10-b6df-17b2c959aaef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_fc2244a2-0e28-46e1-ae7f-41ecc8b5b356" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_fc2244a2-0e28-46e1-ae7f-41ecc8b5b356" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_6e35ac73-5a7f-4d9e-9b99-c78011a72183" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_6e35ac73-5a7f-4d9e-9b99-c78011a72183" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_5ad53666-305f-44af-88e9-c5aea2012538" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_5ad53666-305f-44af-88e9-c5aea2012538" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_171d6893-0f3f-49d1-b413-8b417d9b6818" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_171d6893-0f3f-49d1-b413-8b417d9b6818" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_4855467c-abb0-4e94-9c09-1632c82f6cb4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolving"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolving_4855467c-abb0-4e94-9c09-1632c82f6cb4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan_f0676d98-40ea-4c40-9672-8ed46ad7a670" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan_f0676d98-40ea-4c40-9672-8ed46ad7a670" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_4c1a3473-29f5-4f93-b204-7154dcd02822" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_4c1a3473-29f5-4f93-b204-7154dcd02822" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_d8a57e50-b68c-47c5-81d6-2020cd1f9fb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff_d8a57e50-b68c-47c5-81d6-2020cd1f9fb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_3e0f3b2b-779f-44c2-9559-6fe406d58611" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff_3e0f3b2b-779f-44c2-9559-6fe406d58611" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_6828c929-03f0-490f-9595-beb35208c181" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff_6828c929-03f0-490f-9595-beb35208c181" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_a65bbe8f-3d3b-47ba-8ba5-cb963d87b05f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff_a65bbe8f-3d3b-47ba-8ba5-cb963d87b05f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_75bd8229-4d28-463b-b71e-d6fdd1886adf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff_75bd8229-4d28-463b-b71e-d6fdd1886adf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff_6557dc13-c4ad-4fac-a9b2-065e255eb791" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff_6557dc13-c4ad-4fac-a9b2-065e255eb791" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff_8f814de1-cc02-4a09-9f65-9da243c2866e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff_8f814de1-cc02-4a09-9f65-9da243c2866e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_29f670f3-da16-4761-b622-1734c26119fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract_ed36a62e-2c86-440a-8a10-768ef1c8720f" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_29f670f3-da16-4761-b622-1734c26119fa" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_74ea8b37-5f75-4217-b67d-ba5185dfe17c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_b3c2d3c7-7474-4da9-8d8a-f5a264a5efae" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_74ea8b37-5f75-4217-b67d-ba5185dfe17c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_406770af-40bf-4deb-ab0b-7067a9a3b827" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_74ea8b37-5f75-4217-b67d-ba5185dfe17c" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_406770af-40bf-4deb-ab0b-7067a9a3b827" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_406770af-40bf-4deb-ab0b-7067a9a3b827_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_406770af-40bf-4deb-ab0b-7067a9a3b827" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_406770af-40bf-4deb-ab0b-7067a9a3b827_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71880559-5a3a-45f8-ae60-80fc6f474e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_406770af-40bf-4deb-ab0b-7067a9a3b827" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71880559-5a3a-45f8-ae60-80fc6f474e5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_0e58361c-6b71-4c9b-902f-780e30eb2869" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71880559-5a3a-45f8-ae60-80fc6f474e5f" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_0e58361c-6b71-4c9b-902f-780e30eb2869" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_2b6ba9a2-d24a-4836-916b-9470b656d5b7" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_71880559-5a3a-45f8-ae60-80fc6f474e5f" xlink:to="loc_amal_RetailPortfolioSegmentMember_2b6ba9a2-d24a-4836-916b-9470b656d5b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_0f461ec4-e314-4a77-ad0f-83de18dcf09b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_74ea8b37-5f75-4217-b67d-ba5185dfe17c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_0f461ec4-e314-4a77-ad0f-83de18dcf09b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0f461ec4-e314-4a77-ad0f-83de18dcf09b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_0f461ec4-e314-4a77-ad0f-83de18dcf09b" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0f461ec4-e314-4a77-ad0f-83de18dcf09b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_0f461ec4-e314-4a77-ad0f-83de18dcf09b" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_f6398ab7-1436-4e4c-ab4e-da4e75b650c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_f6398ab7-1436-4e4c-ab4e-da4e75b650c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_52eba40c-9952-48da-a104-b763f64cbde7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_srt_MultifamilyMember_52eba40c-9952-48da-a104-b763f64cbde7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_a1d1c4b3-e707-43be-8318-0219faf8d5c8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_us-gaap_CommercialRealEstateMember_a1d1c4b3-e707-43be-8318-0219faf8d5c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_87600e27-9c8b-4d97-9547-1729ea0800a0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_us-gaap_ConstructionLoansMember_87600e27-9c8b-4d97-9547-1729ea0800a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_66372a37-632e-4b46-b10e-00a7e17e24ec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_us-gaap_ResidentialRealEstateMember_66372a37-632e-4b46-b10e-00a7e17e24ec" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerSolarMember_5318a625-b462-4480-8464-ba690c7e08bf" xlink:href="amal-20230930.xsd#amal_ConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_amal_ConsumerSolarMember_5318a625-b462-4480-8464-ba690c7e08bf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherMember_53d8c1ee-b86d-4700-af8f-ef86e01669c2" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_997589c0-1d3d-46b1-8e0a-a448a621033c" xlink:to="loc_amal_ConsumerAndOtherMember_53d8c1ee-b86d-4700-af8f-ef86e01669c2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_3efda470-ba11-427b-834d-93e528cfe764" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_74ea8b37-5f75-4217-b67d-ba5185dfe17c" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_3efda470-ba11-427b-834d-93e528cfe764" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_3efda470-ba11-427b-834d-93e528cfe764_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_3efda470-ba11-427b-834d-93e528cfe764" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_3efda470-ba11-427b-834d-93e528cfe764_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_cb2020ba-e5b8-412e-bf93-b280378f976f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_3efda470-ba11-427b-834d-93e528cfe764" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_cb2020ba-e5b8-412e-bf93-b280378f976f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PassMember_5fe636f6-28a6-4445-9eba-1eace92c29e8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_cb2020ba-e5b8-412e-bf93-b280378f976f" xlink:to="loc_us-gaap_PassMember_5fe636f6-28a6-4445-9eba-1eace92c29e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SpecialMentionMember_a5d104cf-b3a7-4a8c-a13f-838f62bfde0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SpecialMentionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_cb2020ba-e5b8-412e-bf93-b280378f976f" xlink:to="loc_us-gaap_SpecialMentionMember_a5d104cf-b3a7-4a8c-a13f-838f62bfde0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_8446b536-99a0-4ad1-959a-50a83422cfb1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_cb2020ba-e5b8-412e-bf93-b280378f976f" xlink:to="loc_us-gaap_SubstandardMember_8446b536-99a0-4ad1-959a-50a83422cfb1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DoubtfulMember_4b5099d7-88db-48ae-b5cf-b12ff0f4bc5d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DoubtfulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_cb2020ba-e5b8-412e-bf93-b280378f976f" xlink:to="loc_us-gaap_DoubtfulMember_4b5099d7-88db-48ae-b5cf-b12ff0f4bc5d" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofLoanPortfoliobyCreditQualityIndicatorDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETScheduleofLoanPortfoliobyCreditQualityIndicatorDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofLoanPortfoliobyCreditQualityIndicatorDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_72540d32-61a2-4fba-a918-a8aa4cc60e1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_ec39e922-a3b9-4bc6-8d2e-d55731432cf6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_72540d32-61a2-4fba-a918-a8aa4cc60e1f" xlink:to="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_ec39e922-a3b9-4bc6-8d2e-d55731432cf6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_2e2d2b3b-d20b-4203-8ce0-b7c58441367f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_72540d32-61a2-4fba-a918-a8aa4cc60e1f" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_2e2d2b3b-d20b-4203-8ce0-b7c58441367f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_2750db95-c677-4e83-96c3-1488c9a7d0e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_2e2d2b3b-d20b-4203-8ce0-b7c58441367f" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_2750db95-c677-4e83-96c3-1488c9a7d0e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2750db95-c677-4e83-96c3-1488c9a7d0e5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_2750db95-c677-4e83-96c3-1488c9a7d0e5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2750db95-c677-4e83-96c3-1488c9a7d0e5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0fcdc974-d3ef-4e86-bcca-a95acd5dabdb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_2750db95-c677-4e83-96c3-1488c9a7d0e5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0fcdc974-d3ef-4e86-bcca-a95acd5dabdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_1d1cdf2a-35eb-42fd-b39b-f8cfc413f83d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0fcdc974-d3ef-4e86-bcca-a95acd5dabdb" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_1d1cdf2a-35eb-42fd-b39b-f8cfc413f83d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_6289b755-b83c-492f-a52c-b416f646c1fc" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0fcdc974-d3ef-4e86-bcca-a95acd5dabdb" xlink:to="loc_amal_RetailPortfolioSegmentMember_6289b755-b83c-492f-a52c-b416f646c1fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_8fb430bc-5664-4851-a7d6-2a00785817d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_2e2d2b3b-d20b-4203-8ce0-b7c58441367f" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_8fb430bc-5664-4851-a7d6-2a00785817d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8fb430bc-5664-4851-a7d6-2a00785817d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_8fb430bc-5664-4851-a7d6-2a00785817d4" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_8fb430bc-5664-4851-a7d6-2a00785817d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_8fb430bc-5664-4851-a7d6-2a00785817d4" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_5fb985c8-42b2-4c1f-a5b6-0b35849e0afa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_5fb985c8-42b2-4c1f-a5b6-0b35849e0afa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_dcf6cb59-db7d-40eb-adc6-84874a3c89fe" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:to="loc_srt_MultifamilyMember_dcf6cb59-db7d-40eb-adc6-84874a3c89fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_010b3f6e-aa75-4c77-be16-704c9024543a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:to="loc_us-gaap_CommercialRealEstateMember_010b3f6e-aa75-4c77-be16-704c9024543a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_b0308d71-5b50-4d8e-9632-233c03228675" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:to="loc_us-gaap_ConstructionLoansMember_b0308d71-5b50-4d8e-9632-233c03228675" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_45eabcb1-b534-4e72-88d8-92b800ea0977" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:to="loc_us-gaap_ResidentialRealEstateMember_45eabcb1-b534-4e72-88d8-92b800ea0977" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherAndConsumerSolarMember_eb21fdb4-3b30-46da-a9ac-7f828646d92d" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherAndConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cf30f49a-b95b-42b3-9a72-d113d92b5b1b" xlink:to="loc_amal_ConsumerAndOtherAndConsumerSolarMember_eb21fdb4-3b30-46da-a9ac-7f828646d92d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_61bbcdb5-253d-4d52-b6b7-b233b69715e8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_2e2d2b3b-d20b-4203-8ce0-b7c58441367f" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_61bbcdb5-253d-4d52-b6b7-b233b69715e8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_61bbcdb5-253d-4d52-b6b7-b233b69715e8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_61bbcdb5-253d-4d52-b6b7-b233b69715e8" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_61bbcdb5-253d-4d52-b6b7-b233b69715e8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_e1caf7e2-8d11-4e8f-9c28-640d9a6e83ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_61bbcdb5-253d-4d52-b6b7-b233b69715e8" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_e1caf7e2-8d11-4e8f-9c28-640d9a6e83ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PassMember_6c80d428-16db-4b4d-9b1a-a3fbc50dc3de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_e1caf7e2-8d11-4e8f-9c28-640d9a6e83ef" xlink:to="loc_us-gaap_PassMember_6c80d428-16db-4b4d-9b1a-a3fbc50dc3de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SpecialMentionMember_0383382f-af48-42ca-bfea-3102bb6ba499" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SpecialMentionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_e1caf7e2-8d11-4e8f-9c28-640d9a6e83ef" xlink:to="loc_us-gaap_SpecialMentionMember_0383382f-af48-42ca-bfea-3102bb6ba499" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_271f1004-9db5-4a8f-baa6-d13a8c85fc42" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_e1caf7e2-8d11-4e8f-9c28-640d9a6e83ef" xlink:to="loc_us-gaap_SubstandardMember_271f1004-9db5-4a8f-baa6-d13a8c85fc42" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DoubtfulMember_ac2f1b0f-38d7-4537-9b03-76aba17148b1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DoubtfulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_e1caf7e2-8d11-4e8f-9c28-640d9a6e83ef" xlink:to="loc_us-gaap_DoubtfulMember_ac2f1b0f-38d7-4537-9b03-76aba17148b1" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofActivityinAllowancebyPortfolioDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETScheduleofActivityinAllowancebyPortfolioDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofActivityinAllowancebyPortfolioDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a794150c-67f7-4da9-8d2d-94d8c5027a2e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_180a62d4-252f-4c9f-b649-ed7aad05ef00" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a794150c-67f7-4da9-8d2d-94d8c5027a2e" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_180a62d4-252f-4c9f-b649-ed7aad05ef00" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_c4ac1345-ed8f-4031-98ad-736b32edec16" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_180a62d4-252f-4c9f-b649-ed7aad05ef00" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_c4ac1345-ed8f-4031-98ad-736b32edec16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal_da50941c-26b1-4461-82ec-8585e0be8178" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_180a62d4-252f-4c9f-b649-ed7aad05ef00" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal_da50941c-26b1-4461-82ec-8585e0be8178" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_242c84d6-52a9-4a59-b511-8804ee06c0f3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_180a62d4-252f-4c9f-b649-ed7aad05ef00" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff_242c84d6-52a9-4a59-b511-8804ee06c0f3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery_3afc1d3a-19e9-43f2-b828-691dd879ee4d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_180a62d4-252f-4c9f-b649-ed7aad05ef00" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery_3afc1d3a-19e9-43f2-b828-691dd879ee4d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_b6d40d64-8c10-47ba-9967-11f8757f9bac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_8dcc6212-7824-4682-9a30-0212edbfb8d8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a794150c-67f7-4da9-8d2d-94d8c5027a2e" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_8dcc6212-7824-4682-9a30-0212edbfb8d8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_734bb8d3-1c14-4726-bd59-7bb48732d2ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_8dcc6212-7824-4682-9a30-0212edbfb8d8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_734bb8d3-1c14-4726-bd59-7bb48732d2ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_734bb8d3-1c14-4726-bd59-7bb48732d2ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_734bb8d3-1c14-4726-bd59-7bb48732d2ef" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_734bb8d3-1c14-4726-bd59-7bb48732d2ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_29102ac7-c91f-4d6f-944b-10a72ee723db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_734bb8d3-1c14-4726-bd59-7bb48732d2ef" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_29102ac7-c91f-4d6f-944b-10a72ee723db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_4325879f-edc9-426e-a884-493b40fc0157" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_29102ac7-c91f-4d6f-944b-10a72ee723db" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_4325879f-edc9-426e-a884-493b40fc0157" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_2b88a911-f38a-4939-b73b-8ac155485669" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_29102ac7-c91f-4d6f-944b-10a72ee723db" xlink:to="loc_amal_RetailPortfolioSegmentMember_2b88a911-f38a-4939-b73b-8ac155485669" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_cd8630b3-1c24-46f0-b834-5359348b4252" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_8dcc6212-7824-4682-9a30-0212edbfb8d8" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_cd8630b3-1c24-46f0-b834-5359348b4252" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cd8630b3-1c24-46f0-b834-5359348b4252_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_cd8630b3-1c24-46f0-b834-5359348b4252" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_cd8630b3-1c24-46f0-b834-5359348b4252_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_cd8630b3-1c24-46f0-b834-5359348b4252" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_6607b7f0-8869-48b2-bc78-2a4e19acfeb4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_6607b7f0-8869-48b2-bc78-2a4e19acfeb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_1d490246-8546-4964-9664-41a33eb2051d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_srt_MultifamilyMember_1d490246-8546-4964-9664-41a33eb2051d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_ae331d71-340c-44c6-99d9-dd344b5ef3c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_us-gaap_CommercialRealEstateMember_ae331d71-340c-44c6-99d9-dd344b5ef3c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_41a4c2ad-20f4-4c49-a9aa-c2a6860eb1a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_us-gaap_ConstructionLoansMember_41a4c2ad-20f4-4c49-a9aa-c2a6860eb1a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_d152735e-9c2b-49db-90b7-e22ce292281f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_us-gaap_ResidentialRealEstateMember_d152735e-9c2b-49db-90b7-e22ce292281f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerSolarMember_75404ab3-9352-40a3-998e-482aa997e897" xlink:href="amal-20230930.xsd#amal_ConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_amal_ConsumerSolarMember_75404ab3-9352-40a3-998e-482aa997e897" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherMember_347efb40-ee17-47cf-af20-c62f4147a195" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_953b5546-1cf3-48aa-b709-5749b622146d" xlink:to="loc_amal_ConsumerAndOtherMember_347efb40-ee17-47cf-af20-c62f4147a195" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_666a987d-744e-4641-939d-6447f1407d9d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_8dcc6212-7824-4682-9a30-0212edbfb8d8" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_666a987d-744e-4641-939d-6447f1407d9d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_666a987d-744e-4641-939d-6447f1407d9d_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_666a987d-744e-4641-939d-6447f1407d9d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_666a987d-744e-4641-939d-6447f1407d9d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_b10e3bd6-95b4-4d8b-8ffe-df0b3959cbe2" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_666a987d-744e-4641-939d-6447f1407d9d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_b10e3bd6-95b4-4d8b-8ffe-df0b3959cbe2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_923358f8-5999-4653-bb3b-c4ae8dc1740d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_b10e3bd6-95b4-4d8b-8ffe-df0b3959cbe2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_923358f8-5999-4653-bb3b-c4ae8dc1740d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_4551b445-1b58-47d4-9d89-0d61844b6a41" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_b10e3bd6-95b4-4d8b-8ffe-df0b3959cbe2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_4551b445-1b58-47d4-9d89-0d61844b6a41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9abeda8f-b7ab-4421-ba6d-a4e27f7a7b4d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_8dcc6212-7824-4682-9a30-0212edbfb8d8" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9abeda8f-b7ab-4421-ba6d-a4e27f7a7b4d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_9abeda8f-b7ab-4421-ba6d-a4e27f7a7b4d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9abeda8f-b7ab-4421-ba6d-a4e27f7a7b4d" xlink:to="loc_us-gaap_TypeOfAdoptionMember_9abeda8f-b7ab-4421-ba6d-a4e27f7a7b4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_80cfe8de-d7af-49ca-8f40-d4f790e9ac53" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9abeda8f-b7ab-4421-ba6d-a4e27f7a7b4d" xlink:to="loc_us-gaap_TypeOfAdoptionMember_80cfe8de-d7af-49ca-8f40-d4f790e9ac53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201613Member_007d0bed-5918-44ac-b480-9310e84c7677" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate201613Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_80cfe8de-d7af-49ca-8f40-d4f790e9ac53" xlink:to="loc_us-gaap_AccountingStandardsUpdate201613Member_007d0bed-5918-44ac-b480-9310e84c7677" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETNonaccrualDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETNonaccrualDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETNonaccrualDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_1afeb98f-25b4-4218-a435-b27ca97ec72c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableNonaccrualStatusLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance_e78c1788-86d6-4de5-b324-0eaf0480f2a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_1afeb98f-25b4-4218-a435-b27ca97ec72c" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance_e78c1788-86d6-4de5-b324-0eaf0480f2a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual_b95edc70-a0ab-4881-9f19-ba019563d03f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_1afeb98f-25b4-4218-a435-b27ca97ec72c" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual_b95edc70-a0ab-4881-9f19-ba019563d03f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_FinancingReceivableExcludingAccruedInterestReserve_ad52095a-9756-4bc4-9f97-77af4d66e649" xlink:href="amal-20230930.xsd#amal_FinancingReceivableExcludingAccruedInterestReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_1afeb98f-25b4-4218-a435-b27ca97ec72c" xlink:to="loc_amal_FinancingReceivableExcludingAccruedInterestReserve_ad52095a-9756-4bc4-9f97-77af4d66e649" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualTable_06fa1f54-1519-47f7-8098-c92579fc2920" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableNonaccrualTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_1afeb98f-25b4-4218-a435-b27ca97ec72c" xlink:to="loc_us-gaap_FinancingReceivableNonaccrualTable_06fa1f54-1519-47f7-8098-c92579fc2920" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_0553b9e0-e451-4486-b95c-10ead86bcb0b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualTable_06fa1f54-1519-47f7-8098-c92579fc2920" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_0553b9e0-e451-4486-b95c-10ead86bcb0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0553b9e0-e451-4486-b95c-10ead86bcb0b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_0553b9e0-e451-4486-b95c-10ead86bcb0b" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_0553b9e0-e451-4486-b95c-10ead86bcb0b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6336b13d-8d6b-4561-b7df-ee8269427ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_0553b9e0-e451-4486-b95c-10ead86bcb0b" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6336b13d-8d6b-4561-b7df-ee8269427ac6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_d989e422-6ed7-4f10-899a-d2bf29de146f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6336b13d-8d6b-4561-b7df-ee8269427ac6" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_d989e422-6ed7-4f10-899a-d2bf29de146f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_2769b0c7-31e7-44f1-aa59-756a3f67ad32" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_6336b13d-8d6b-4561-b7df-ee8269427ac6" xlink:to="loc_amal_RetailPortfolioSegmentMember_2769b0c7-31e7-44f1-aa59-756a3f67ad32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_806e5636-867c-4faf-910c-9ce8b2a0063a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualTable_06fa1f54-1519-47f7-8098-c92579fc2920" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_806e5636-867c-4faf-910c-9ce8b2a0063a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_806e5636-867c-4faf-910c-9ce8b2a0063a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_806e5636-867c-4faf-910c-9ce8b2a0063a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_806e5636-867c-4faf-910c-9ce8b2a0063a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_806e5636-867c-4faf-910c-9ce8b2a0063a" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_8fc3a19b-d2fb-4a83-9c45-452eb9a6e66a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_8fc3a19b-d2fb-4a83-9c45-452eb9a6e66a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_a99a2871-4e71-478b-ae46-ca63bd6df3fe" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_srt_MultifamilyMember_a99a2871-4e71-478b-ae46-ca63bd6df3fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_2b2ee1fb-9170-4c12-a3b0-a0b9658b8caf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_us-gaap_CommercialRealEstateMember_2b2ee1fb-9170-4c12-a3b0-a0b9658b8caf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_ed54d76b-7782-4609-b407-0a347ab2b28d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_us-gaap_ConstructionLoansMember_ed54d76b-7782-4609-b407-0a347ab2b28d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_5b0127ad-be11-4b88-b80a-72a09364ae1a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_us-gaap_ResidentialRealEstateMember_5b0127ad-be11-4b88-b80a-72a09364ae1a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerSolarMember_5d51c153-8d28-4775-a18e-a7795a972d77" xlink:href="amal-20230930.xsd#amal_ConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_amal_ConsumerSolarMember_5d51c153-8d28-4775-a18e-a7795a972d77" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherMember_353f31ee-21d9-440a-b8f8-926dfd76f024" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_0cd46bd4-dca2-4920-b81a-387f1a38e254" xlink:to="loc_amal_ConsumerAndOtherMember_353f31ee-21d9-440a-b8f8-926dfd76f024" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETDependentCollateralDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETDependentCollateralDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETDependentCollateralDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_6fe880f2-059d-4e88-a81a-7bbc748e89cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_880a4a2c-6b54-430c-b1a3-2932f3947617" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_6fe880f2-059d-4e88-a81a-7bbc748e89cd" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_880a4a2c-6b54-430c-b1a3-2932f3947617" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_07d4701a-6ffd-49ca-b074-4dbb124031e8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_6fe880f2-059d-4e88-a81a-7bbc748e89cd" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_07d4701a-6ffd-49ca-b074-4dbb124031e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_b49dde83-3c97-471c-ab9f-575b57269c76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_6fe880f2-059d-4e88-a81a-7bbc748e89cd" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_b49dde83-3c97-471c-ab9f-575b57269c76" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAxis_dbbe95d8-43e1-4f05-85ec-997c2f28b1da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CollateralAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_b49dde83-3c97-471c-ab9f-575b57269c76" xlink:to="loc_us-gaap_CollateralAxis_dbbe95d8-43e1-4f05-85ec-997c2f28b1da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_dbbe95d8-43e1-4f05-85ec-997c2f28b1da_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_dbbe95d8-43e1-4f05-85ec-997c2f28b1da" xlink:to="loc_us-gaap_CollateralDomain_dbbe95d8-43e1-4f05-85ec-997c2f28b1da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralDomain_95a69933-79fe-4e72-b3ed-21690ed2de57" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CollateralDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_dbbe95d8-43e1-4f05-85ec-997c2f28b1da" xlink:to="loc_us-gaap_CollateralDomain_95a69933-79fe-4e72-b3ed-21690ed2de57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_b27c45f8-80a3-4967-9b13-98dfff5ec1da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_95a69933-79fe-4e72-b3ed-21690ed2de57" xlink:to="loc_us-gaap_CommercialRealEstateMember_b27c45f8-80a3-4967-9b13-98dfff5ec1da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_bcd5888f-b469-4a4b-a7ee-f4f480dbfbcb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_b49dde83-3c97-471c-ab9f-575b57269c76" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_bcd5888f-b469-4a4b-a7ee-f4f480dbfbcb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_bcd5888f-b469-4a4b-a7ee-f4f480dbfbcb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_bcd5888f-b469-4a4b-a7ee-f4f480dbfbcb" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_bcd5888f-b469-4a4b-a7ee-f4f480dbfbcb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_b168c49d-da42-48b4-b0ab-21a16e381b49" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_bcd5888f-b469-4a4b-a7ee-f4f480dbfbcb" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_b168c49d-da42-48b4-b0ab-21a16e381b49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_5dc9dc2b-21db-476c-a49c-8b4b04ef665b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_b168c49d-da42-48b4-b0ab-21a16e381b49" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_5dc9dc2b-21db-476c-a49c-8b4b04ef665b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_16ba2010-be1a-4252-9fa0-8ec6ed9ec26f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_b49dde83-3c97-471c-ab9f-575b57269c76" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_16ba2010-be1a-4252-9fa0-8ec6ed9ec26f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_16ba2010-be1a-4252-9fa0-8ec6ed9ec26f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_16ba2010-be1a-4252-9fa0-8ec6ed9ec26f" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_16ba2010-be1a-4252-9fa0-8ec6ed9ec26f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_07e813b7-96f5-45e2-a7c7-9c21cd9fa376" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_16ba2010-be1a-4252-9fa0-8ec6ed9ec26f" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_07e813b7-96f5-45e2-a7c7-9c21cd9fa376" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_5d01557e-65e7-4306-a82d-3d9a70a5fcb9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_07e813b7-96f5-45e2-a7c7-9c21cd9fa376" xlink:to="loc_us-gaap_CommercialRealEstateMember_5d01557e-65e7-4306-a82d-3d9a70a5fcb9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_d6470a30-f863-4ad9-804f-a5eba02c47a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_07e813b7-96f5-45e2-a7c7-9c21cd9fa376" xlink:to="loc_us-gaap_ConstructionLoansMember_d6470a30-f863-4ad9-804f-a5eba02c47a8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETMethodofEvaluatingImpairmentofLoansandAllowanceDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETMethodofEvaluatingImpairmentofLoansandAllowanceDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETMethodofEvaluatingImpairmentofLoansandAllowanceDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a47b842b-96c2-4dfd-8600-f44a7a676d68" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAbstract_aa610810-d307-4ec6-99fe-31041e5c8fe5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a47b842b-96c2-4dfd-8600-f44a7a676d68" xlink:to="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAbstract_aa610810-d307-4ec6-99fe-31041e5c8fe5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_e232a71a-8c2b-4efa-8120-f4c76589f31a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAbstract_aa610810-d307-4ec6-99fe-31041e5c8fe5" xlink:to="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_e232a71a-8c2b-4efa-8120-f4c76589f31a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_72060b2e-90c5-4d30-a348-2d5d9f0763b7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAbstract_aa610810-d307-4ec6-99fe-31041e5c8fe5" xlink:to="loc_us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_72060b2e-90c5-4d30-a348-2d5d9f0763b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_e04d3fca-0645-4c4b-91ac-41c9fb23d64a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAbstract_aa610810-d307-4ec6-99fe-31041e5c8fe5" xlink:to="loc_us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee_e04d3fca-0645-4c4b-91ac-41c9fb23d64a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_a8121325-2baf-44d7-bf7e-841250b26970" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a47b842b-96c2-4dfd-8600-f44a7a676d68" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_a8121325-2baf-44d7-bf7e-841250b26970" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_96d4f19f-3eb6-4d74-b718-a3c432bb1d7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_a8121325-2baf-44d7-bf7e-841250b26970" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_96d4f19f-3eb6-4d74-b718-a3c432bb1d7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_ba62828d-8e8b-484e-abe8-329f824f2525" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_a8121325-2baf-44d7-bf7e-841250b26970" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_ba62828d-8e8b-484e-abe8-329f824f2525" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_8a8439f5-0922-424a-8806-f91aa187c95c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossAbstract_a8121325-2baf-44d7-bf7e-841250b26970" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest_8a8439f5-0922-424a-8806-f91aa187c95c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_71215cf4-e137-4bd2-b416-5e7bc2b53c03" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_a47b842b-96c2-4dfd-8600-f44a7a676d68" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_71215cf4-e137-4bd2-b416-5e7bc2b53c03" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a0208ee4-118c-4328-9085-c219ce6b63e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_71215cf4-e137-4bd2-b416-5e7bc2b53c03" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a0208ee4-118c-4328-9085-c219ce6b63e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a0208ee4-118c-4328-9085-c219ce6b63e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a0208ee4-118c-4328-9085-c219ce6b63e3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a0208ee4-118c-4328-9085-c219ce6b63e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2df529e4-cf30-4674-866d-69d4df7be9c8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a0208ee4-118c-4328-9085-c219ce6b63e3" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2df529e4-cf30-4674-866d-69d4df7be9c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_f7346270-0948-4e32-a340-ebf999ba0baf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2df529e4-cf30-4674-866d-69d4df7be9c8" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_f7346270-0948-4e32-a340-ebf999ba0baf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_abb5407f-d2fa-4fd2-9835-05c23f1d8131" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2df529e4-cf30-4674-866d-69d4df7be9c8" xlink:to="loc_amal_RetailPortfolioSegmentMember_abb5407f-d2fa-4fd2-9835-05c23f1d8131" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_79b87a59-ef90-4f0a-bffa-be2489e0df99" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_71215cf4-e137-4bd2-b416-5e7bc2b53c03" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_79b87a59-ef90-4f0a-bffa-be2489e0df99" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_79b87a59-ef90-4f0a-bffa-be2489e0df99_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_79b87a59-ef90-4f0a-bffa-be2489e0df99" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_79b87a59-ef90-4f0a-bffa-be2489e0df99_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_79b87a59-ef90-4f0a-bffa-be2489e0df99" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_7947ffd9-c27d-43a9-a4c7-dea2c28d985c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_7947ffd9-c27d-43a9-a4c7-dea2c28d985c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_f3c606f3-803a-4288-8d5d-c84590f4e4a3" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:to="loc_srt_MultifamilyMember_f3c606f3-803a-4288-8d5d-c84590f4e4a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_71530f82-24b5-47c0-80bd-58c5de93e201" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:to="loc_us-gaap_CommercialRealEstateMember_71530f82-24b5-47c0-80bd-58c5de93e201" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_82d05723-c78d-45af-bc5b-c3f7b843fb74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:to="loc_us-gaap_ConstructionLoansMember_82d05723-c78d-45af-bc5b-c3f7b843fb74" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_4ea75a93-9652-4a12-b0ae-e1c8c06ad7af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:to="loc_us-gaap_ResidentialRealEstateMember_4ea75a93-9652-4a12-b0ae-e1c8c06ad7af" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ConsumerAndOtherAndConsumerSolarMember_d825416b-923a-4756-bd30-03f3d1e73ecf" xlink:href="amal-20230930.xsd#amal_ConsumerAndOtherAndConsumerSolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_4f39c8b9-8c57-4b76-ba20-76d78b77bf24" xlink:to="loc_amal_ConsumerAndOtherAndConsumerSolarMember_d825416b-923a-4756-bd30-03f3d1e73ecf" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofIndividuallyImpairedLoansandAllowancesDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#LOANSRECEIVABLENETScheduleofIndividuallyImpairedLoansandAllowancesDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/LOANSRECEIVABLENETScheduleofIndividuallyImpairedLoansandAllowancesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableImpairedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_dcf83b0c-bc95-447e-a2ff-087fc5d19ae5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_dcf83b0c-bc95-447e-a2ff-087fc5d19ae5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_2a8ee326-01f7-4cc4-a009-a1a03863f95b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_2a8ee326-01f7-4cc4-a009-a1a03863f95b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_420548bd-48f1-4f30-90f2-73cc14e420ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_420548bd-48f1-4f30-90f2-73cc14e420ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_34875234-9806-4907-9714-33cbf9ee6262" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_34875234-9806-4907-9714-33cbf9ee6262" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_b6a1b77b-2a93-47b1-96cb-35bb28540935" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_b6a1b77b-2a93-47b1-96cb-35bb28540935" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_d440d6dc-df1b-438c-a11b-9a019e22d43b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_d440d6dc-df1b-438c-a11b-9a019e22d43b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_f269bf0f-9068-48e1-9ef8-bd45dba6fe26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_f269bf0f-9068-48e1-9ef8-bd45dba6fe26" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_2bbec10a-a3a4-483e-b213-c1ea5f1df174" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_2bbec10a-a3a4-483e-b213-c1ea5f1df174" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_6cdfc6f7-dc7b-406a-8fe3-62b5506358cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_6cdfc6f7-dc7b-406a-8fe3-62b5506358cc" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_7fdd7f8d-7f7f-4aae-aea1-1e5fdb055bac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairedFinancingReceivableRelatedAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_7fdd7f8d-7f7f-4aae-aea1-1e5fdb055bac" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_d2560065-7384-4c2e-ac61-aff39e55468c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfImpairedFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_e56e7746-7942-4c62-bdfd-c946c6f3e035" xlink:to="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_d2560065-7384-4c2e-ac61-aff39e55468c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_b8b0a516-6f49-46a1-a5d2-3da18db52097" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_d2560065-7384-4c2e-ac61-aff39e55468c" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_b8b0a516-6f49-46a1-a5d2-3da18db52097" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_b8b0a516-6f49-46a1-a5d2-3da18db52097_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_b8b0a516-6f49-46a1-a5d2-3da18db52097" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_b8b0a516-6f49-46a1-a5d2-3da18db52097_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_dafe0f8b-34e9-4746-b8ec-0b51dadcd3fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_b8b0a516-6f49-46a1-a5d2-3da18db52097" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_dafe0f8b-34e9-4746-b8ec-0b51dadcd3fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_RetailPortfolioSegmentMember_2d6818a0-8ffa-462a-91ec-b95f0a2ffa7d" xlink:href="amal-20230930.xsd#amal_RetailPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_dafe0f8b-34e9-4746-b8ec-0b51dadcd3fa" xlink:to="loc_amal_RetailPortfolioSegmentMember_2d6818a0-8ffa-462a-91ec-b95f0a2ffa7d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_61d2c2ff-b7c8-489a-8479-faba767a1d71" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_dafe0f8b-34e9-4746-b8ec-0b51dadcd3fa" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_61d2c2ff-b7c8-489a-8479-faba767a1d71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_7b40b8de-f612-4ab5-b525-156c22aabf5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_d2560065-7384-4c2e-ac61-aff39e55468c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_7b40b8de-f612-4ab5-b525-156c22aabf5e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_7b40b8de-f612-4ab5-b525-156c22aabf5e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_7b40b8de-f612-4ab5-b525-156c22aabf5e" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_7b40b8de-f612-4ab5-b525-156c22aabf5e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_7b40b8de-f612-4ab5-b525-156c22aabf5e" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialRealEstateMember_3cffbd76-63c5-42d0-bfca-a68921ebd423" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:to="loc_us-gaap_ResidentialRealEstateMember_3cffbd76-63c5-42d0-bfca-a68921ebd423" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MultifamilyMember_6405e49a-45d4-49bf-9186-38d6c1f0f3f7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MultifamilyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:to="loc_srt_MultifamilyMember_6405e49a-45d4-49bf-9186-38d6c1f0f3f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionLoansMember_734fe4ab-8fad-424d-ac64-53e5e2d8cfc7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:to="loc_us-gaap_ConstructionLoansMember_734fe4ab-8fad-424d-ac64-53e5e2d8cfc7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstateMember_4b88c1ba-a483-4b3b-830d-2466c029c4d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:to="loc_us-gaap_CommercialRealEstateMember_4b88c1ba-a483-4b3b-830d-2466c029c4d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialAndIndustrialSectorMember_093a0cfa-0ebb-4233-a4a0-0fd06b94b56c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialAndIndustrialSectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_5bb54763-1cef-4e18-a692-cfdf44fd5543" xlink:to="loc_us-gaap_CommercialAndIndustrialSectorMember_093a0cfa-0ebb-4233-a4a0-0fd06b94b56c" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/BORROWEDFUNDSDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#BORROWEDFUNDSDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/BORROWEDFUNDSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_02933c21-9502-40d7-890f-a13db3cea10e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_02933c21-9502-40d7-890f-a13db3cea10e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_ad4e1ed8-6819-4e20-8abd-4654e07e67ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankAdvancesLongTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:to="loc_us-gaap_FederalHomeLoanBankAdvancesLongTerm_ad4e1ed8-6819-4e20-8abd-4654e07e67ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm_8c933996-0c27-4cc1-97e3-ba9ccdc88601" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:to="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm_8c933996-0c27-4cc1-97e3-ba9ccdc88601" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherBorrowings_2274d994-2590-46e6-bc71-0e8f873510b3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:to="loc_us-gaap_OtherBorrowings_2274d994-2590-46e6-bc71-0e8f873510b3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalFundsPurchased_efdbd8b7-93a3-4140-afe1-8e6b1bb09168" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpenseFederalFundsPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:to="loc_us-gaap_InterestExpenseFederalFundsPurchased_efdbd8b7-93a3-4140-afe1-8e6b1bb09168" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTable_d445fd35-0a45-4986-96df-0cf34cef8811" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems_60fdc020-3dc6-42f1-8e80-fb7e9b435544" xlink:to="loc_us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTable_d445fd35-0a45-4986-96df-0cf34cef8811" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_d8746421-6a8b-40ff-a639-b18a928d5785" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTable_d445fd35-0a45-4986-96df-0cf34cef8811" xlink:to="loc_us-gaap_FinancialInstrumentAxis_d8746421-6a8b-40ff-a639-b18a928d5785" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d8746421-6a8b-40ff-a639-b18a928d5785_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d8746421-6a8b-40ff-a639-b18a928d5785" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d8746421-6a8b-40ff-a639-b18a928d5785_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fdf031fb-ae23-448c-8b2b-877a4f25e4ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d8746421-6a8b-40ff-a639-b18a928d5785" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fdf031fb-ae23-448c-8b2b-877a4f25e4ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralizedSecuritiesOtherMember_e8e416b9-90ff-4172-8672-a6c1e293cab9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CollateralizedSecuritiesOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fdf031fb-ae23-448c-8b2b-877a4f25e4ca" xlink:to="loc_us-gaap_CollateralizedSecuritiesOtherMember_e8e416b9-90ff-4172-8672-a6c1e293cab9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_a8bd9d87-aaa8-45e6-8f7b-30b57430eed2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fdf031fb-ae23-448c-8b2b-877a4f25e4ca" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_a8bd9d87-aaa8-45e6-8f7b-30b57430eed2" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/SUBORDINATEDDEBTDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#SUBORDINATEDDEBTDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/SUBORDINATEDDEBTDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebt_8a61f6cd-ca66-4463-a434-226b9bc6be90" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubordinatedDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_SubordinatedDebt_8a61f6cd-ca66-4463-a434-226b9bc6be90" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_ed441e9f-15c7-4eb0-b81f-0a34d882c388" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_ed441e9f-15c7-4eb0-b81f-0a34d882c388" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_b8357caa-82a5-4a48-8926-2eabf186fd33" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_b8357caa-82a5-4a48-8926-2eabf186fd33" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_c546f72f-a531-4faa-b512-047197202eea" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_c546f72f-a531-4faa-b512-047197202eea" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_d950798b-1122-400f-aaa5-1b38a7aee99e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestExpenseSubordinatedNotesAndDebentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_InterestExpenseSubordinatedNotesAndDebentures_d950798b-1122-400f-aaa5-1b38a7aee99e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_DebtInstrumentRepurchaseAmountParValue_ca155c19-6353-4cbd-ae22-91ef574164be" xlink:href="amal-20230930.xsd#amal_DebtInstrumentRepurchaseAmountParValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_amal_DebtInstrumentRepurchaseAmountParValue_ca155c19-6353-4cbd-ae22-91ef574164be" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ProceedsFromRepaymentsOfSubordinatedDebt_1e99125a-af85-498c-9d33-f38063d34d69" xlink:href="amal-20230930.xsd#amal_ProceedsFromRepaymentsOfSubordinatedDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_amal_ProceedsFromRepaymentsOfSubordinatedDebt_1e99125a-af85-498c-9d33-f38063d34d69" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnRepurchaseOfDebtInstrument_ea075191-dd5b-442c-93c7-b0b405f36240" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnRepurchaseOfDebtInstrument"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_GainLossOnRepurchaseOfDebtInstrument_ea075191-dd5b-442c-93c7-b0b405f36240" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralTable_b420a560-a354-45fa-9141-2319699404ec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralLineItems_6be5a696-bd84-4c26-8f49-e6bb134f355f" xlink:to="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralTable_b420a560-a354-45fa-9141-2319699404ec" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_de719f66-7b6e-417d-8fa3-d7fdafd99566" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralTable_b420a560-a354-45fa-9141-2319699404ec" xlink:to="loc_us-gaap_DebtInstrumentAxis_de719f66-7b6e-417d-8fa3-d7fdafd99566" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_de719f66-7b6e-417d-8fa3-d7fdafd99566_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_de719f66-7b6e-417d-8fa3-d7fdafd99566" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_de719f66-7b6e-417d-8fa3-d7fdafd99566_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9dba06d5-4835-4d0e-9c5c-2cbaa080d9e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_de719f66-7b6e-417d-8fa3-d7fdafd99566" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9dba06d5-4835-4d0e-9c5c-2cbaa080d9e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_FixedToFloatingRateNotesMember_0e5866b9-2e0a-4df1-ae6d-029af8582648" xlink:href="amal-20230930.xsd#amal_FixedToFloatingRateNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9dba06d5-4835-4d0e-9c5c-2cbaa080d9e1" xlink:to="loc_amal_FixedToFloatingRateNotesMember_0e5866b9-2e0a-4df1-ae6d-029af8582648" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_1b6a4bdd-3a65-4015-a229-ed419acb1c07" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralTable_b420a560-a354-45fa-9141-2319699404ec" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_1b6a4bdd-3a65-4015-a229-ed419acb1c07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1b6a4bdd-3a65-4015-a229-ed419acb1c07_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1b6a4bdd-3a65-4015-a229-ed419acb1c07" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1b6a4bdd-3a65-4015-a229-ed419acb1c07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_69608318-86a2-4a00-a329-5ddeb99b0126" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1b6a4bdd-3a65-4015-a229-ed419acb1c07" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_69608318-86a2-4a00-a329-5ddeb99b0126" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_fb8fb680-598c-48d2-b6b8-07b932286e25" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubordinatedDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_69608318-86a2-4a00-a329-5ddeb99b0126" xlink:to="loc_us-gaap_SubordinatedDebtMember_fb8fb680-598c-48d2-b6b8-07b932286e25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_f5b70a88-429e-4894-ba8e-684aca58266d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancialInstrumentsOwnedAndPledgedAsCollateralTable_b420a560-a354-45fa-9141-2319699404ec" xlink:to="loc_us-gaap_VariableRateAxis_f5b70a88-429e-4894-ba8e-684aca58266d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_f5b70a88-429e-4894-ba8e-684aca58266d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_f5b70a88-429e-4894-ba8e-684aca58266d" xlink:to="loc_us-gaap_VariableRateDomain_f5b70a88-429e-4894-ba8e-684aca58266d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_1f0c63fd-a7d8-410a-ae03-773dc56b4964" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_f5b70a88-429e-4894-ba8e-684aca58266d" xlink:to="loc_us-gaap_VariableRateDomain_1f0c63fd-a7d8-410a-ae03-773dc56b4964" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_SecuredOvernightFinancingRateSOFRMember_06b8bd0d-5739-43c0-adad-0665659099b4" xlink:href="amal-20230930.xsd#amal_SecuredOvernightFinancingRateSOFRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_1f0c63fd-a7d8-410a-ae03-773dc56b4964" xlink:to="loc_amal_SecuredOvernightFinancingRateSOFRMember_06b8bd0d-5739-43c0-adad-0665659099b4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/EMPLOYEEBENEFITPLANSNarrativeDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#EMPLOYEEBENEFITPLANSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/EMPLOYEEBENEFITPLANSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_3775e265-c871-4eb6-9744-83e7986cde05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_3775e265-c871-4eb6-9744-83e7986cde05" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_4ebde57c-c158-423a-bc12-9c835539a5e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_4ebde57c-c158-423a-bc12-9c835539a5e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_ae85a981-6a66-42a6-ac13-55d8b3f82abb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_ae85a981-6a66-42a6-ac13-55d8b3f82abb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_30b8c42a-893c-4df9-8132-48fb4180da4b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_30b8c42a-893c-4df9-8132-48fb4180da4b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_3ef84984-376e-4f3c-80c2-545087313596" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_3ef84984-376e-4f3c-80c2-545087313596" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_9da95e69-0e32-4da8-b43e-b12da886d5d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_9da95e69-0e32-4da8-b43e-b12da886d5d2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_d6f2ef3b-f63f-4bd9-824d-dcac9ead961e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_d6f2ef3b-f63f-4bd9-824d-dcac9ead961e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_d1fc226e-0c61-4956-b379-d258fbff1a04" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_d1fc226e-0c61-4956-b379-d258fbff1a04" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d2e55099-cdb9-4f1d-9f25-f1af9b69608d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d2e55099-cdb9-4f1d-9f25-f1af9b69608d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_21f6b560-7537-4801-8cac-c423652a3bf1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_21f6b560-7537-4801-8cac-c423652a3bf1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_7ea9f68e-4e8a-40cd-80e2-ae837dbf2c0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_7ea9f68e-4e8a-40cd-80e2-ae837dbf2c0d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNumberOfAwardsAchievable_7199ae27-6821-4d02-9e69-e97acf40bc94" xlink:href="amal-20230930.xsd#amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNumberOfAwardsAchievable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNumberOfAwardsAchievable_7199ae27-6821-4d02-9e69-e97acf40bc94" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_2c9d3a47-98a2-4d3a-91db-a5b41134e3d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_2c9d3a47-98a2-4d3a-91db-a5b41134e3d2" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_22f21998-ce52-40e1-a0ec-9058454b70fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_22f21998-ce52-40e1-a0ec-9058454b70fe" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_198f0ca4-cb6e-4b11-8f5b-4a95785d9b19" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_198f0ca4-cb6e-4b11-8f5b-4a95785d9b19" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_f8ac02e5-868b-4c51-ba1e-9e159be0613a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_f8ac02e5-868b-4c51-ba1e-9e159be0613a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_58e5c445-a185-45cf-b54c-bb0b22261ab6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_58e5c445-a185-45cf-b54c-bb0b22261ab6" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_a0ed26aa-e942-418e-8da3-c42ace72dc00" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_a0ed26aa-e942-418e-8da3-c42ace72dc00" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumPurchaseValueDuringYearPerEmployee_440f5e7b-3643-44ee-a809-51ebdcd7cdac" xlink:href="amal-20230930.xsd#amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumPurchaseValueDuringYearPerEmployee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumPurchaseValueDuringYearPerEmployee_440f5e7b-3643-44ee-a809-51ebdcd7cdac" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_96138cf4-7a85-4f0e-a992-99f46aa821ff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_96138cf4-7a85-4f0e-a992-99f46aa821ff" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictionPeriod_4698174c-585b-43cf-9d27-874ea3fbee7a" xlink:href="amal-20230930.xsd#amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_amal_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictionPeriod_4698174c-585b-43cf-9d27-874ea3fbee7a" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c427ac05-c6f6-4ac5-9722-5bb91b9319a3" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_de2b053d-f0c1-4e27-9dc9-c742ba3909ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:to="loc_us-gaap_AwardTypeAxis_de2b053d-f0c1-4e27-9dc9-c742ba3909ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_de2b053d-f0c1-4e27-9dc9-c742ba3909ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_de2b053d-f0c1-4e27-9dc9-c742ba3909ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_de2b053d-f0c1-4e27-9dc9-c742ba3909ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_577e9b5b-9149-4dbc-8f60-173b625d509a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_de2b053d-f0c1-4e27-9dc9-c742ba3909ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_577e9b5b-9149-4dbc-8f60-173b625d509a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_f1d092c6-0f3f-4efd-a7e6-0644d946b46b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_577e9b5b-9149-4dbc-8f60-173b625d509a" xlink:to="loc_us-gaap_EmployeeStockOptionMember_f1d092c6-0f3f-4efd-a7e6-0644d946b46b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_3c381b48-781e-4740-b9c3-6df61f04e16e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_577e9b5b-9149-4dbc-8f60-173b625d509a" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_3c381b48-781e-4740-b9c3-6df61f04e16e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_e0ff28a1-1250-4f3d-bad9-2371be0ec9c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedStockUnitsRSUMember_3c381b48-781e-4740-b9c3-6df61f04e16e" xlink:to="loc_us-gaap_PerformanceSharesMember_e0ff28a1-1250-4f3d-bad9-2371be0ec9c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MarketBasedRestrictedStockUnitsMember_89d2892d-3e1f-43b9-a55a-f3c1f089ec4f" xlink:href="amal-20230930.xsd#amal_MarketBasedRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedStockUnitsRSUMember_3c381b48-781e-4740-b9c3-6df61f04e16e" xlink:to="loc_amal_MarketBasedRestrictedStockUnitsMember_89d2892d-3e1f-43b9-a55a-f3c1f089ec4f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_4d2f8815-add8-472a-9d39-d7150701a375" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_577e9b5b-9149-4dbc-8f60-173b625d509a" xlink:to="loc_us-gaap_EmployeeStockMember_4d2f8815-add8-472a-9d39-d7150701a375" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusAxis_a3292a7c-4a21-467d-a500-cd22b8c37b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GranteeStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:to="loc_us-gaap_GranteeStatusAxis_a3292a7c-4a21-467d-a500-cd22b8c37b2c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusDomain_a3292a7c-4a21-467d-a500-cd22b8c37b2c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GranteeStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GranteeStatusAxis_a3292a7c-4a21-467d-a500-cd22b8c37b2c" xlink:to="loc_us-gaap_GranteeStatusDomain_a3292a7c-4a21-467d-a500-cd22b8c37b2c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusDomain_fb0eb076-f430-4f9a-96d5-6ada1af1f192" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GranteeStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GranteeStatusAxis_a3292a7c-4a21-467d-a500-cd22b8c37b2c" xlink:to="loc_us-gaap_GranteeStatusDomain_fb0eb076-f430-4f9a-96d5-6ada1af1f192" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedPaymentArrangementEmployeeMember_67670db4-9aa0-4a03-ba80-facd55434c6d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedPaymentArrangementEmployeeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GranteeStatusDomain_fb0eb076-f430-4f9a-96d5-6ada1af1f192" xlink:to="loc_us-gaap_ShareBasedPaymentArrangementEmployeeMember_67670db4-9aa0-4a03-ba80-facd55434c6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_765a15a0-5c33-4d91-9a28-4fa90f8ffe2d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:to="loc_srt_RangeAxis_765a15a0-5c33-4d91-9a28-4fa90f8ffe2d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_765a15a0-5c33-4d91-9a28-4fa90f8ffe2d_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_765a15a0-5c33-4d91-9a28-4fa90f8ffe2d" xlink:to="loc_srt_RangeMember_765a15a0-5c33-4d91-9a28-4fa90f8ffe2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1448909d-832b-4684-bd9c-dc47f533fcc6" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_765a15a0-5c33-4d91-9a28-4fa90f8ffe2d" xlink:to="loc_srt_RangeMember_1448909d-832b-4684-bd9c-dc47f533fcc6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_0201b2ab-cff1-4713-b819-31a01f4514eb" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_1448909d-832b-4684-bd9c-dc47f533fcc6" xlink:to="loc_srt_MinimumMember_0201b2ab-cff1-4713-b819-31a01f4514eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_14b5bf82-7a8d-493d-a136-31a14d2b482f" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_1448909d-832b-4684-bd9c-dc47f533fcc6" xlink:to="loc_srt_MaximumMember_14b5bf82-7a8d-493d-a136-31a14d2b482f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_2981a8ab-5d81-4fbe-8390-397203c4e92c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:to="loc_srt_TitleOfIndividualAxis_2981a8ab-5d81-4fbe-8390-397203c4e92c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2981a8ab-5d81-4fbe-8390-397203c4e92c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_2981a8ab-5d81-4fbe-8390-397203c4e92c" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2981a8ab-5d81-4fbe-8390-397203c4e92c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_a976ecd3-861b-4e51-bdb4-9695c8600c01" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_2981a8ab-5d81-4fbe-8390-397203c4e92c" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_a976ecd3-861b-4e51-bdb4-9695c8600c01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_DirectorMember_0265c545-31c0-4a3f-9628-5b590e37d168" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_DirectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_a976ecd3-861b-4e51-bdb4-9695c8600c01" xlink:to="loc_srt_DirectorMember_0265c545-31c0-4a3f-9628-5b590e37d168" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_GrantDateFairValueAxis_28ee69f0-9415-46f9-b266-09a40ee000f7" xlink:href="amal-20230930.xsd#amal_GrantDateFairValueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_43337238-d2e7-49f7-938b-1443c88a1ad2" xlink:to="loc_amal_GrantDateFairValueAxis_28ee69f0-9415-46f9-b266-09a40ee000f7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_GrantDateFairValueDomain_28ee69f0-9415-46f9-b266-09a40ee000f7_default" xlink:href="amal-20230930.xsd#amal_GrantDateFairValueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_amal_GrantDateFairValueAxis_28ee69f0-9415-46f9-b266-09a40ee000f7" xlink:to="loc_amal_GrantDateFairValueDomain_28ee69f0-9415-46f9-b266-09a40ee000f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_GrantDateFairValueDomain_7c47271e-c9e4-47d3-8889-7877417ea8d3" xlink:href="amal-20230930.xsd#amal_GrantDateFairValueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_amal_GrantDateFairValueAxis_28ee69f0-9415-46f9-b266-09a40ee000f7" xlink:to="loc_amal_GrantDateFairValueDomain_7c47271e-c9e4-47d3-8889-7877417ea8d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_GrantDateFairValueOneMember_7cb6ea67-ac1e-4537-a53f-c4d12d0e2662" xlink:href="amal-20230930.xsd#amal_GrantDateFairValueOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_GrantDateFairValueDomain_7c47271e-c9e4-47d3-8889-7877417ea8d3" xlink:to="loc_amal_GrantDateFairValueOneMember_7cb6ea67-ac1e-4537-a53f-c4d12d0e2662" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_GrantDateFairValueTwoMember_a09d6e10-dfe9-474b-a8db-64138dea229e" xlink:href="amal-20230930.xsd#amal_GrantDateFairValueTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_GrantDateFairValueDomain_7c47271e-c9e4-47d3-8889-7877417ea8d3" xlink:to="loc_amal_GrantDateFairValueTwoMember_a09d6e10-dfe9-474b-a8db-64138dea229e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_GrantDateFairValueThreeMember_e3266ff1-6bde-4996-89a6-0eec6440fe37" xlink:href="amal-20230930.xsd#amal_GrantDateFairValueThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amal_GrantDateFairValueDomain_7c47271e-c9e4-47d3-8889-7877417ea8d3" xlink:to="loc_amal_GrantDateFairValueThreeMember_e3266ff1-6bde-4996-89a6-0eec6440fe37" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/EMPLOYEEBENEFITPLANSRestrictedStockUnitsActivityDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#EMPLOYEEBENEFITPLANSRestrictedStockUnitsActivityDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/EMPLOYEEBENEFITPLANSRestrictedStockUnitsActivityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47c556d4-c917-4596-929a-dc8075b23eed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_bfa96821-2d72-40b9-9535-669837e65d54" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47c556d4-c917-4596-929a-dc8075b23eed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_bfa96821-2d72-40b9-9535-669837e65d54" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_b5e28136-b6cd-468c-9cf4-02ff4d0cb7ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_bfa96821-2d72-40b9-9535-669837e65d54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_b5e28136-b6cd-468c-9cf4-02ff4d0cb7ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_ff639868-9185-48b8-a111-a36d1f48c359" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_bfa96821-2d72-40b9-9535-669837e65d54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_ff639868-9185-48b8-a111-a36d1f48c359" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_b67cbd42-dffc-4a77-bce3-415a7b0ca611" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_bfa96821-2d72-40b9-9535-669837e65d54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_b67cbd42-dffc-4a77-bce3-415a7b0ca611" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_eaaaff7b-14e4-43f6-9937-feffcdd17a20" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_bfa96821-2d72-40b9-9535-669837e65d54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_eaaaff7b-14e4-43f6-9937-feffcdd17a20" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_985d8107-0b08-4cfa-8955-8243d98c6bda" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_ac59b042-45d9-4e01-92a5-2ff42485c804" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47c556d4-c917-4596-929a-dc8075b23eed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_ac59b042-45d9-4e01-92a5-2ff42485c804" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_91a4e72d-9388-477d-ab4b-1902516ea087" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_ac59b042-45d9-4e01-92a5-2ff42485c804" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_91a4e72d-9388-477d-ab4b-1902516ea087" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_c6fa4058-e285-441a-8f47-2ab47cf12db0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_ac59b042-45d9-4e01-92a5-2ff42485c804" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_c6fa4058-e285-441a-8f47-2ab47cf12db0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_d49c1815-c80a-40e7-8a62-c7b23bbbde8c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_ac59b042-45d9-4e01-92a5-2ff42485c804" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_d49c1815-c80a-40e7-8a62-c7b23bbbde8c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_05e5ce01-05fd-47e1-909b-b623f78d6799" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_ac59b042-45d9-4e01-92a5-2ff42485c804" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_05e5ce01-05fd-47e1-909b-b623f78d6799" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_24ff092e-dd84-475c-a25d-5f4155bf24dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_467d1479-9906-4366-ba1a-e063623ad31c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47c556d4-c917-4596-929a-dc8075b23eed" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_467d1479-9906-4366-ba1a-e063623ad31c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_fc5185f0-f8ae-4dbe-ac29-cae781c0d297" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_467d1479-9906-4366-ba1a-e063623ad31c" xlink:to="loc_us-gaap_AwardTypeAxis_fc5185f0-f8ae-4dbe-ac29-cae781c0d297" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fc5185f0-f8ae-4dbe-ac29-cae781c0d297_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_fc5185f0-f8ae-4dbe-ac29-cae781c0d297" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fc5185f0-f8ae-4dbe-ac29-cae781c0d297_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5bb50a40-b825-4100-b585-438ce1a10214" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_fc5185f0-f8ae-4dbe-ac29-cae781c0d297" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5bb50a40-b825-4100-b585-438ce1a10214" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_53feef8a-c65d-4d71-abd5-e691b7f23bfd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5bb50a40-b825-4100-b585-438ce1a10214" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_53feef8a-c65d-4d71-abd5-e691b7f23bfd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_f15a82af-2261-4002-bd71-64952f997edb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5bb50a40-b825-4100-b585-438ce1a10214" xlink:to="loc_us-gaap_PerformanceSharesMember_f15a82af-2261-4002-bd71-64952f997edb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusAxis_f884234d-95a5-44d9-937e-bb7c903c55ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GranteeStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_467d1479-9906-4366-ba1a-e063623ad31c" xlink:to="loc_us-gaap_GranteeStatusAxis_f884234d-95a5-44d9-937e-bb7c903c55ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusDomain_f884234d-95a5-44d9-937e-bb7c903c55ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GranteeStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GranteeStatusAxis_f884234d-95a5-44d9-937e-bb7c903c55ed" xlink:to="loc_us-gaap_GranteeStatusDomain_f884234d-95a5-44d9-937e-bb7c903c55ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusDomain_6907a578-c94f-462e-8ee4-0857b94cb22e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GranteeStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GranteeStatusAxis_f884234d-95a5-44d9-937e-bb7c903c55ed" xlink:to="loc_us-gaap_GranteeStatusDomain_6907a578-c94f-462e-8ee4-0857b94cb22e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedPaymentArrangementEmployeeMember_876b3eb8-082b-4d2c-ab64-d08feb28bee0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedPaymentArrangementEmployeeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GranteeStatusDomain_6907a578-c94f-462e-8ee4-0857b94cb22e" xlink:to="loc_us-gaap_ShareBasedPaymentArrangementEmployeeMember_876b3eb8-082b-4d2c-ab64-d08feb28bee0" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/EMPLOYEEBENEFITPLANSESPPDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#EMPLOYEEBENEFITPLANSESPPDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/EMPLOYEEBENEFITPLANSESPPDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cd25c458-3420-4127-87ea-f0333b9614c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_37abfcda-8e3c-45e4-9ac4-67707b32c56c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cd25c458-3420-4127-87ea-f0333b9614c6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_37abfcda-8e3c-45e4-9ac4-67707b32c56c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_c02a4861-6584-4980-a164-43381cd6fa58" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_37abfcda-8e3c-45e4-9ac4-67707b32c56c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_c02a4861-6584-4980-a164-43381cd6fa58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_7f78432a-792d-43cf-95d4-d44ef8c56d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_37abfcda-8e3c-45e4-9ac4-67707b32c56c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_7f78432a-792d-43cf-95d4-d44ef8c56d1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_fd8fe8dc-a7f9-4015-a6ae-f1bb1adc0fd7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_7f78432a-792d-43cf-95d4-d44ef8c56d1f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_fd8fe8dc-a7f9-4015-a6ae-f1bb1adc0fd7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_ddfedb65-a5b6-4be1-b553-1deeae36df3b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3079c975-ce19-476a-9372-d491308d11bc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cd25c458-3420-4127-87ea-f0333b9614c6" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3079c975-ce19-476a-9372-d491308d11bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_521c734d-a5a1-4cc5-a158-4dc4f9f4b935" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3079c975-ce19-476a-9372-d491308d11bc" xlink:to="loc_us-gaap_AwardTypeAxis_521c734d-a5a1-4cc5-a158-4dc4f9f4b935" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_521c734d-a5a1-4cc5-a158-4dc4f9f4b935_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_521c734d-a5a1-4cc5-a158-4dc4f9f4b935" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_521c734d-a5a1-4cc5-a158-4dc4f9f4b935_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a88a2804-67a4-478d-a66d-0182dc731659" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_521c734d-a5a1-4cc5-a158-4dc4f9f4b935" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a88a2804-67a4-478d-a66d-0182dc731659" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_7635a90b-0bf6-4eea-93eb-a517cdc14837" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a88a2804-67a4-478d-a66d-0182dc731659" xlink:to="loc_us-gaap_EmployeeStockMember_7635a90b-0bf6-4eea-93eb-a517cdc14837" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSScheduleofFairValueofAssetsMeasuredonRecurringBasisDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSScheduleofFairValueofAssetsMeasuredonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSScheduleofFairValueofAssetsMeasuredonRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_283da705-4559-463f-9166-7cbe4619d3c2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_bb4a5439-2009-4cf3-90df-1a16cdb2fd7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_283da705-4559-463f-9166-7cbe4619d3c2" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_bb4a5439-2009-4cf3-90df-1a16cdb2fd7c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_37e151a0-29b2-4903-975e-355009495809" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_283da705-4559-463f-9166-7cbe4619d3c2" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_37e151a0-29b2-4903-975e-355009495809" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_f64ae080-5879-4bbf-96fc-06bfc65582a6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_37e151a0-29b2-4903-975e-355009495809" xlink:to="loc_us-gaap_FinancialInstrumentAxis_f64ae080-5879-4bbf-96fc-06bfc65582a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f64ae080-5879-4bbf-96fc-06bfc65582a6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_f64ae080-5879-4bbf-96fc-06bfc65582a6" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f64ae080-5879-4bbf-96fc-06bfc65582a6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_bf409293-ee2a-4522-9bcb-d1496adb528b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_f64ae080-5879-4bbf-96fc-06bfc65582a6" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_bf409293-ee2a-4522-9bcb-d1496adb528b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_81c50b5d-911e-40f2-8144-c418e7c53ed6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_bf409293-ee2a-4522-9bcb-d1496adb528b" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_81c50b5d-911e-40f2-8144-c418e7c53ed6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_09082e2d-06c1-4b55-a991-1aa7afdf470a" xlink:href="amal-20230930.xsd#amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_81c50b5d-911e-40f2-8144-c418e7c53ed6" xlink:to="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesResidentialCollateralizedMortgageObligationsMember_09082e2d-06c1-4b55-a991-1aa7afdf470a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember_95972ad9-128a-4fcc-8331-27c09515e41e" xlink:href="amal-20230930.xsd#amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_81c50b5d-911e-40f2-8144-c418e7c53ed6" xlink:to="loc_amal_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEntitiesCommercialCertificatesAndCollateralizedMortgageObligationsMember_95972ad9-128a-4fcc-8331-27c09515e41e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_6b3db4d4-52cf-44c7-8b62-b14b9abbbf71" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_81c50b5d-911e-40f2-8144-c418e7c53ed6" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_6b3db4d4-52cf-44c7-8b62-b14b9abbbf71" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_16f34d7f-de30-4899-8b11-3848306d2aaf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MortgageBackedSecuritiesMember_81c50b5d-911e-40f2-8144-c418e7c53ed6" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_16f34d7f-de30-4899-8b11-3848306d2aaf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_bf409293-ee2a-4522-9bcb-d1496adb528b" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_49343db8-62be-461f-b5ee-aa5bfdb44799" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_49343db8-62be-461f-b5ee-aa5bfdb44799" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_4d10e51f-7191-4964-aa41-f11cecf8a6ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:to="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_4d10e51f-7191-4964-aa41-f11cecf8a6ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TrustPreferredSecuritiesMember_f97a35cc-3785-47b8-b1b2-a2b86a6d3c51" xlink:href="amal-20230930.xsd#amal_TrustPreferredSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:to="loc_amal_TrustPreferredSecuritiesMember_f97a35cc-3785-47b8-b1b2-a2b86a6d3c51" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_857f5f91-d0ff-46c7-8edf-adc702dc46e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_857f5f91-d0ff-46c7-8edf-adc702dc46e1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_1930371e-18ef-4de6-aa53-3252957363ef" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherDebtSecuritiesMember_01bdf81d-d520-475a-97b2-5684490336ed" xlink:to="loc_amal_PropertyAssessedCleanEnergyAssessmentSecuritiesResidentialMember_1930371e-18ef-4de6-aa53-3252957363ef" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_1d2ce8a2-b64d-49d6-9edb-cb56c709b5df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_37e151a0-29b2-4903-975e-355009495809" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_1d2ce8a2-b64d-49d6-9edb-cb56c709b5df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_1d2ce8a2-b64d-49d6-9edb-cb56c709b5df_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_1d2ce8a2-b64d-49d6-9edb-cb56c709b5df" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_1d2ce8a2-b64d-49d6-9edb-cb56c709b5df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_ccce1f05-7b1e-4960-89d8-3e85b9fe1431" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_1d2ce8a2-b64d-49d6-9edb-cb56c709b5df" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_ccce1f05-7b1e-4960-89d8-3e85b9fe1431" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_41cf1b6b-4dc6-438b-8c2a-a70b001c7d4f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_ccce1f05-7b1e-4960-89d8-3e85b9fe1431" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_41cf1b6b-4dc6-438b-8c2a-a70b001c7d4f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcf5122a-0ae6-45f0-88fb-906b2bfa493b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_37e151a0-29b2-4903-975e-355009495809" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcf5122a-0ae6-45f0-88fb-906b2bfa493b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dcf5122a-0ae6-45f0-88fb-906b2bfa493b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcf5122a-0ae6-45f0-88fb-906b2bfa493b" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_dcf5122a-0ae6-45f0-88fb-906b2bfa493b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b2a35709-555c-418c-8d09-fa73192f33f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_dcf5122a-0ae6-45f0-88fb-906b2bfa493b" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b2a35709-555c-418c-8d09-fa73192f33f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_3056ceec-ba7a-4b44-aa9b-f2bcb08ad5ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b2a35709-555c-418c-8d09-fa73192f33f0" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_3056ceec-ba7a-4b44-aa9b-f2bcb08ad5ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_184a393a-9970-4886-8db3-c97ece58ef72" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b2a35709-555c-418c-8d09-fa73192f33f0" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_184a393a-9970-4886-8db3-c97ece58ef72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_ef7a5efa-0ff2-4c1e-940c-66b0a065612f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b2a35709-555c-418c-8d09-fa73192f33f0" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_ef7a5efa-0ff2-4c1e-940c-66b0a065612f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSSecuritiesMeasuredonNonRecurringBasisDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSSecuritiesMeasuredonNonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSSecuritiesMeasuredonNonRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6607d2f8-4595-403d-8b32-4cd1987b425f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_IndividuallyAnalyzedFinancingReceivableFairValueDisclosure_af2cfff8-9b88-47c4-9f53-6d2be9285c24" xlink:href="amal-20230930.xsd#amal_IndividuallyAnalyzedFinancingReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6607d2f8-4595-403d-8b32-4cd1987b425f" xlink:to="loc_amal_IndividuallyAnalyzedFinancingReceivableFairValueDisclosure_af2cfff8-9b88-47c4-9f53-6d2be9285c24" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_ImpairedFinancingReceivableFairValueDisclosure_c32db31c-1ec7-4b56-bfc7-63b554bf4824" xlink:href="amal-20230930.xsd#amal_ImpairedFinancingReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6607d2f8-4595-403d-8b32-4cd1987b425f" xlink:to="loc_amal_ImpairedFinancingReceivableFairValueDisclosure_c32db31c-1ec7-4b56-bfc7-63b554bf4824" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_05c0666f-4330-45c8-a132-cea1011530c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6607d2f8-4595-403d-8b32-4cd1987b425f" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_05c0666f-4330-45c8-a132-cea1011530c7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_22a9635d-b589-438a-896d-3dc1e6cbfa67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_05c0666f-4330-45c8-a132-cea1011530c7" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_22a9635d-b589-438a-896d-3dc1e6cbfa67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_22a9635d-b589-438a-896d-3dc1e6cbfa67_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_22a9635d-b589-438a-896d-3dc1e6cbfa67" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_22a9635d-b589-438a-896d-3dc1e6cbfa67_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_d438d03f-42d4-4147-b525-190755943735" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_22a9635d-b589-438a-896d-3dc1e6cbfa67" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_d438d03f-42d4-4147-b525-190755943735" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_47ae7d14-2387-4b80-9268-aa288c9617d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_d438d03f-42d4-4147-b525-190755943735" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_47ae7d14-2387-4b80-9268-aa288c9617d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_5f5ae4c9-69e6-42ae-8a80-668818610d3d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_d438d03f-42d4-4147-b525-190755943735" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_5f5ae4c9-69e6-42ae-8a80-668818610d3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_1dee1595-695c-4b65-9c4e-95d2bd65301b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_d438d03f-42d4-4147-b525-190755943735" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_1dee1595-695c-4b65-9c4e-95d2bd65301b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_bcda829e-d215-482d-991b-13cd983da641" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_05c0666f-4330-45c8-a132-cea1011530c7" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_bcda829e-d215-482d-991b-13cd983da641" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_bcda829e-d215-482d-991b-13cd983da641_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_bcda829e-d215-482d-991b-13cd983da641" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_bcda829e-d215-482d-991b-13cd983da641_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_6e97a49d-10b8-45f3-8666-79e857adb507" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_bcda829e-d215-482d-991b-13cd983da641" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_6e97a49d-10b8-45f3-8666-79e857adb507" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_d0657821-d51e-40a7-a0cc-ed70ed999d94" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_6e97a49d-10b8-45f3-8666-79e857adb507" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_d0657821-d51e-40a7-a0cc-ed70ed999d94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_40b274b9-f3b4-4c7d-b94d-ca05811466cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_05c0666f-4330-45c8-a132-cea1011530c7" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_40b274b9-f3b4-4c7d-b94d-ca05811466cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_40b274b9-f3b4-4c7d-b94d-ca05811466cc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_40b274b9-f3b4-4c7d-b94d-ca05811466cc" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_40b274b9-f3b4-4c7d-b94d-ca05811466cc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_55ce34ea-cd17-495c-9be8-53c8dc1dff7a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_40b274b9-f3b4-4c7d-b94d-ca05811466cc" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_55ce34ea-cd17-495c-9be8-53c8dc1dff7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_c1515f55-fe68-4328-a66d-1876aef501d8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_55ce34ea-cd17-495c-9be8-53c8dc1dff7a" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_c1515f55-fe68-4328-a66d-1876aef501d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_9d55d7ef-69c5-4677-bdb5-ff0f90fee4d1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_55ce34ea-cd17-495c-9be8-53c8dc1dff7a" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_9d55d7ef-69c5-4677-bdb5-ff0f90fee4d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_d06c6434-abce-4da8-abae-56c8a5fecf43" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_55ce34ea-cd17-495c-9be8-53c8dc1dff7a" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_d06c6434-abce-4da8-abae-56c8a5fecf43" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSScheduleofBasisandEstimatedFairValuesofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#FAIRVALUEOFFINANCIALINSTRUMENTSScheduleofBasisandEstimatedFairValuesofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSScheduleofBasisandEstimatedFairValuesofFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7cbc5ff9-1433-4db2-bef6-dc634d06f62e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7cbc5ff9-1433-4db2-bef6-dc634d06f62e" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_5e663241-4e94-4550-b22e-6f2fdbe09454" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_5e663241-4e94-4550-b22e-6f2fdbe09454" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_95d7d0e2-67ee-44c1-919c-793148374817" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_95d7d0e2-67ee-44c1-919c-793148374817" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_8952541d-ed3b-461b-9209-473b6ce2cf1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoansHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_us-gaap_LoansHeldForSaleFairValueDisclosure_8952541d-ed3b-461b-9209-473b6ce2cf1f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_6056c2d0-d1b3-4b9e-8ba2-0b0468acdf87" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LoansReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_6056c2d0-d1b3-4b9e-8ba2-0b0468acdf87" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AccruedInterestReceivableFairValueDisclosure_7972a900-9ed5-4645-8c08-66c625c763b4" xlink:href="amal-20230930.xsd#amal_AccruedInterestReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_amal_AccruedInterestReceivableFairValueDisclosure_7972a900-9ed5-4645-8c08-66c625c763b4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsSoldAndSecuritiesBorrowedOrPurchasedUnderAgreementsToResellFairValueDisclosure_9bc96165-79f6-4d63-8970-f289b807c2e4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalFundsSoldAndSecuritiesBorrowedOrPurchasedUnderAgreementsToResellFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_us-gaap_FederalFundsSoldAndSecuritiesBorrowedOrPurchasedUnderAgreementsToResellFairValueDisclosure_9bc96165-79f6-4d63-8970-f289b807c2e4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_AccruedInterestAndDividendsReceivableFairValueDisclosure_b29c469b-41a7-4d5b-83a2-8fe0a8394145" xlink:href="amal-20230930.xsd#amal_AccruedInterestAndDividendsReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e00be2c6-eb55-466b-9052-2fb809043c9e" xlink:to="loc_amal_AccruedInterestAndDividendsReceivableFairValueDisclosure_b29c469b-41a7-4d5b-83a2-8fe0a8394145" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7cbc5ff9-1433-4db2-bef6-dc634d06f62e" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsFairValueDisclosure_cb827052-7e1b-4ce1-bf0b-f2982f71dbb0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DepositsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:to="loc_us-gaap_DepositsFairValueDisclosure_cb827052-7e1b-4ce1-bf0b-f2982f71dbb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_b9cfb4ac-3394-4869-a307-8d2329c615de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:to="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_b9cfb4ac-3394-4869-a307-8d2329c615de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_8fbccb39-ec4f-4614-af24-f89d70ecf118" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:to="loc_us-gaap_DebtInstrumentFairValue_8fbccb39-ec4f-4614-af24-f89d70ecf118" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_cf14d9da-d7c1-4fa3-8b21-9b541b3f69d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_cf14d9da-d7c1-4fa3-8b21-9b541b3f69d4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesFairValueDisclosure_7ef65191-b5ee-47b1-bba3-72d388764e45" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_9218d013-83b9-474b-85c1-d06792877693" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesFairValueDisclosure_7ef65191-b5ee-47b1-bba3-72d388764e45" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1e766cb1-d373-43da-814a-06d16dc4d4dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_7cbc5ff9-1433-4db2-bef6-dc634d06f62e" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1e766cb1-d373-43da-814a-06d16dc4d4dd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_0f69d138-c474-430a-a7e8-f9f942135b88" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1e766cb1-d373-43da-814a-06d16dc4d4dd" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_0f69d138-c474-430a-a7e8-f9f942135b88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0f69d138-c474-430a-a7e8-f9f942135b88_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_0f69d138-c474-430a-a7e8-f9f942135b88" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0f69d138-c474-430a-a7e8-f9f942135b88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_fb3f8ed5-b021-4f4f-a550-b0371bc8145f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_0f69d138-c474-430a-a7e8-f9f942135b88" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_fb3f8ed5-b021-4f4f-a550-b0371bc8145f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_671bef53-f803-4c84-9b97-1157b77a3367" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_fb3f8ed5-b021-4f4f-a550-b0371bc8145f" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_671bef53-f803-4c84-9b97-1157b77a3367" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_04f0e5cf-6de6-46ec-bebf-de68b82b4487" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_fb3f8ed5-b021-4f4f-a550-b0371bc8145f" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_04f0e5cf-6de6-46ec-bebf-de68b82b4487" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_ea77da42-2952-4d0c-b102-96e6c10fc9dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_fb3f8ed5-b021-4f4f-a550-b0371bc8145f" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_ea77da42-2952-4d0c-b102-96e6c10fc9dc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e65aab5e-02ed-4e47-ba26-36c899803e2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1e766cb1-d373-43da-814a-06d16dc4d4dd" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e65aab5e-02ed-4e47-ba26-36c899803e2d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e65aab5e-02ed-4e47-ba26-36c899803e2d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e65aab5e-02ed-4e47-ba26-36c899803e2d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e65aab5e-02ed-4e47-ba26-36c899803e2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7c2a3d8e-62cb-4fb0-a94a-c2ff3d6083f3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e65aab5e-02ed-4e47-ba26-36c899803e2d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7c2a3d8e-62cb-4fb0-a94a-c2ff3d6083f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_078cdcbe-7b2c-4988-a17c-f9d2058bbcc1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7c2a3d8e-62cb-4fb0-a94a-c2ff3d6083f3" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_078cdcbe-7b2c-4988-a17c-f9d2058bbcc1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_c4a1814d-54fd-41b8-af7f-9e84fdf212d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7c2a3d8e-62cb-4fb0-a94a-c2ff3d6083f3" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_c4a1814d-54fd-41b8-af7f-9e84fdf212d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_6e0f98f0-5187-46d7-95b5-b3c4c13912b4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7c2a3d8e-62cb-4fb0-a94a-c2ff3d6083f3" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_6e0f98f0-5187-46d7-95b5-b3c4c13912b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_b2e7fba8-4298-48e8-8b7b-27cba3f6adab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1e766cb1-d373-43da-814a-06d16dc4d4dd" xlink:to="loc_us-gaap_FinancialInstrumentAxis_b2e7fba8-4298-48e8-8b7b-27cba3f6adab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b2e7fba8-4298-48e8-8b7b-27cba3f6adab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b2e7fba8-4298-48e8-8b7b-27cba3f6adab" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b2e7fba8-4298-48e8-8b7b-27cba3f6adab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d646a446-2bc8-43a7-93a7-37fe7c31a61e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b2e7fba8-4298-48e8-8b7b-27cba3f6adab" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d646a446-2bc8-43a7-93a7-37fe7c31a61e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DemandDepositsMember_63662a45-e767-4e08-8b12-ea5e4636125b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DemandDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d646a446-2bc8-43a7-93a7-37fe7c31a61e" xlink:to="loc_us-gaap_DemandDepositsMember_63662a45-e767-4e08-8b12-ea5e4636125b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsMember_93c8cd07-574b-4dd3-912e-3f6f62c31ca5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d646a446-2bc8-43a7-93a7-37fe7c31a61e" xlink:to="loc_us-gaap_DepositsMember_93c8cd07-574b-4dd3-912e-3f6f62c31ca5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsPurchasedMember_1dc943e0-d9ed-4a50-92a3-32cf467b3526" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FederalFundsPurchasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d646a446-2bc8-43a7-93a7-37fe7c31a61e" xlink:to="loc_us-gaap_FederalFundsPurchasedMember_1dc943e0-d9ed-4a50-92a3-32cf467b3526" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETRISKScheduleofFinancialInstrumentsOutstandingRepresentingCreditRiskDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETRISKScheduleofFinancialInstrumentsOutstandingRepresentingCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETRISKScheduleofFinancialInstrumentsOutstandingRepresentingCreditRiskDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_2bff40c8-7ec5-4e86-850a-d5e09226d932" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure_0d6b164e-81c9-4c82-8cdb-41cad316f530" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_2bff40c8-7ec5-4e86-850a-d5e09226d932" xlink:to="loc_us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure_0d6b164e-81c9-4c82-8cdb-41cad316f530" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_5dcc460b-7143-473a-8889-51d276397af8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_2bff40c8-7ec5-4e86-850a-d5e09226d932" xlink:to="loc_us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_5dcc460b-7143-473a-8889-51d276397af8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_c4de2940-d661-49a9-9484-d5ad664c48fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_5dcc460b-7143-473a-8889-51d276397af8" xlink:to="loc_us-gaap_FinancialInstrumentAxis_c4de2940-d661-49a9-9484-d5ad664c48fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c4de2940-d661-49a9-9484-d5ad664c48fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_c4de2940-d661-49a9-9484-d5ad664c48fd" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c4de2940-d661-49a9-9484-d5ad664c48fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_287517b0-dd78-4eed-8171-95ffc03ee658" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_c4de2940-d661-49a9-9484-d5ad664c48fd" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_287517b0-dd78-4eed-8171-95ffc03ee658" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsToExtendCreditMember_49e59dea-40b9-4f2f-a06d-f5d10e31518e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommitmentsToExtendCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_287517b0-dd78-4eed-8171-95ffc03ee658" xlink:to="loc_us-gaap_CommitmentsToExtendCreditMember_49e59dea-40b9-4f2f-a06d-f5d10e31518e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_8d706071-9f17-4a1f-9bc9-ee864a20f8c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_287517b0-dd78-4eed-8171-95ffc03ee658" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_8d706071-9f17-4a1f-9bc9-ee864a20f8c0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETRISKNarrativeDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETRISKNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETRISKNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems_a37e2c59-c2a2-4923-9613-5039077a5575" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiability_5557da9a-9855-4fe8-9df5-a86d5b9634f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OffBalanceSheetCreditLossLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems_a37e2c59-c2a2-4923-9613-5039077a5575" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiability_5557da9a-9855-4fe8-9df5-a86d5b9634f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_fab3e184-a604-4b54-9e99-dfa5be545b3e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems_a37e2c59-c2a2-4923-9613-5039077a5575" xlink:to="loc_us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal_fab3e184-a604-4b54-9e99-dfa5be545b3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PurchaseObligationAmountFulfilled_54ed84a3-3077-4a41-96d8-152f274e993a" xlink:href="amal-20230930.xsd#amal_PurchaseObligationAmountFulfilled"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems_a37e2c59-c2a2-4923-9613-5039077a5575" xlink:to="loc_amal_PurchaseObligationAmountFulfilled_54ed84a3-3077-4a41-96d8-152f274e993a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted_be3c484e-8ce7-4e7c-94ee-df4979f4738d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems_a37e2c59-c2a2-4923-9613-5039077a5575" xlink:to="loc_us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted_be3c484e-8ce7-4e7c-94ee-df4979f4738d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentTable_9bfc53a5-6cbd-4f70-b35f-67d8915c6604" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PurchaseCommitmentExcludingLongtermCommitmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems_a37e2c59-c2a2-4923-9613-5039077a5575" xlink:to="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentTable_9bfc53a5-6cbd-4f70-b35f-67d8915c6604" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis_8a0a8f19-e3bb-4f07-aaa6-73e4138e8cce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentTable_9bfc53a5-6cbd-4f70-b35f-67d8915c6604" xlink:to="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis_8a0a8f19-e3bb-4f07-aaa6-73e4138e8cce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain_8a0a8f19-e3bb-4f07-aaa6-73e4138e8cce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis_8a0a8f19-e3bb-4f07-aaa6-73e4138e8cce" xlink:to="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain_8a0a8f19-e3bb-4f07-aaa6-73e4138e8cce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain_ee66f205-8ebb-4e82-b8f5-1ff7e5c5968a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis_8a0a8f19-e3bb-4f07-aaa6-73e4138e8cce" xlink:to="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain_ee66f205-8ebb-4e82-b8f5-1ff7e5c5968a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_PropertyAssessedCleanEnergyCommitmentsMember_dd8e57db-6318-45c3-9667-65306af2075f" xlink:href="amal-20230930.xsd#amal_PropertyAssessedCleanEnergyCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentDomain_ee66f205-8ebb-4e82-b8f5-1ff7e5c5968a" xlink:to="loc_amal_PropertyAssessedCleanEnergyCommitmentsMember_dd8e57db-6318-45c3-9667-65306af2075f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_394b02ce-3563-4ce7-aba3-fb29ce1ff230" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PurchaseCommitmentExcludingLongtermCommitmentTable_9bfc53a5-6cbd-4f70-b35f-67d8915c6604" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_394b02ce-3563-4ce7-aba3-fb29ce1ff230" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_394b02ce-3563-4ce7-aba3-fb29ce1ff230_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_394b02ce-3563-4ce7-aba3-fb29ce1ff230" xlink:to="loc_us-gaap_TypeOfAdoptionMember_394b02ce-3563-4ce7-aba3-fb29ce1ff230_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_387d631c-9e3f-46a0-879b-8b135a0bfaec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_394b02ce-3563-4ce7-aba3-fb29ce1ff230" xlink:to="loc_us-gaap_TypeOfAdoptionMember_387d631c-9e3f-46a0-879b-8b135a0bfaec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201613Member_1e52f355-6e9b-45cd-9f51-f09cad559d28" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate201613Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_387d631c-9e3f-46a0-879b-8b135a0bfaec" xlink:to="loc_us-gaap_AccountingStandardsUpdate201613Member_1e52f355-6e9b-45cd-9f51-f09cad559d28" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/VARIABLEINTERESTENTITIESUnconsolidatedVariableInterestEntitiesDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#VARIABLEINTERESTENTITIESUnconsolidatedVariableInterestEntitiesDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/VARIABLEINTERESTENTITIESUnconsolidatedVariableInterestEntitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_83d2d3fd-b184-48f8-aa3f-0c81fb2a9618" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_EquityInvestmentsTaxCreditInvestment_21656c79-e0a1-4d23-bdef-eb75942550c1" xlink:href="amal-20230930.xsd#amal_EquityInvestmentsTaxCreditInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_83d2d3fd-b184-48f8-aa3f-0c81fb2a9618" xlink:to="loc_amal_EquityInvestmentsTaxCreditInvestment_21656c79-e0a1-4d23-bdef-eb75942550c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TaxCreditInvestmentsCommitment_919c1c54-9e22-4862-8752-84be7ea29efc" xlink:href="amal-20230930.xsd#amal_TaxCreditInvestmentsCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_83d2d3fd-b184-48f8-aa3f-0c81fb2a9618" xlink:to="loc_amal_TaxCreditInvestmentsCommitment_919c1c54-9e22-4862-8752-84be7ea29efc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_TaxCreditInvestmentsFundedPortionOfCommitment_c216c4ac-5f68-49dc-9376-a2bc3ee48ac2" xlink:href="amal-20230930.xsd#amal_TaxCreditInvestmentsFundedPortionOfCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_83d2d3fd-b184-48f8-aa3f-0c81fb2a9618" xlink:to="loc_amal_TaxCreditInvestmentsFundedPortionOfCommitment_c216c4ac-5f68-49dc-9376-a2bc3ee48ac2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_0a756fa9-91bd-4588-bc50-6276ab9831fb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_83d2d3fd-b184-48f8-aa3f-0c81fb2a9618" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_0a756fa9-91bd-4588-bc50-6276ab9831fb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_8a3a962d-b95f-4b24-852f-df5ae89e279c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_0a756fa9-91bd-4588-bc50-6276ab9831fb" xlink:to="loc_srt_ConsolidatedEntitiesAxis_8a3a962d-b95f-4b24-852f-df5ae89e279c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_8a3a962d-b95f-4b24-852f-df5ae89e279c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_8a3a962d-b95f-4b24-852f-df5ae89e279c" xlink:to="loc_srt_ConsolidatedEntitiesDomain_8a3a962d-b95f-4b24-852f-df5ae89e279c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_427cab90-f794-4cb5-ac90-c7c5942d11db" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_8a3a962d-b95f-4b24-852f-df5ae89e279c" xlink:to="loc_srt_ConsolidatedEntitiesDomain_427cab90-f794-4cb5-ac90-c7c5942d11db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_0a320244-f0c2-4530-af0f-54c752e9b2c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_427cab90-f794-4cb5-ac90-c7c5942d11db" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_0a320244-f0c2-4530-af0f-54c752e9b2c1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amalgamatedbank.com/role/VARIABLEINTERESTENTITIESTaxCreditBenefitsDetails" xlink:type="simple" xlink:href="amal-20230930.xsd#VARIABLEINTERESTENTITIESTaxCreditBenefitsDetails"/>
  <link:definitionLink xlink:role="http://www.amalgamatedbank.com/role/VARIABLEINTERESTENTITIESTaxCreditBenefitsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_4f064a38-2eb8-4c12-9e97-1678db202733" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTaxCredit_a9ae66fa-3c07-47c5-bc06-20c8a11ac9cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentTaxCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4f064a38-2eb8-4c12-9e97-1678db202733" xlink:to="loc_us-gaap_InvestmentTaxCredit_a9ae66fa-3c07-47c5-bc06-20c8a11ac9cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_5b73d55a-9346-4545-bbfe-33b3eb0bf341" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4f064a38-2eb8-4c12-9e97-1678db202733" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_5b73d55a-9346-4545-bbfe-33b3eb0bf341" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_8237937a-d96e-439a-b756-a11379bee1b9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_5b73d55a-9346-4545-bbfe-33b3eb0bf341" xlink:to="loc_srt_ConsolidatedEntitiesAxis_8237937a-d96e-439a-b756-a11379bee1b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_8237937a-d96e-439a-b756-a11379bee1b9_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_8237937a-d96e-439a-b756-a11379bee1b9" xlink:to="loc_srt_ConsolidatedEntitiesDomain_8237937a-d96e-439a-b756-a11379bee1b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_65fb46ec-72cf-45e0-afc9-a1a82b2a265b" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_8237937a-d96e-439a-b756-a11379bee1b9" xlink:to="loc_srt_ConsolidatedEntitiesDomain_65fb46ec-72cf-45e0-afc9-a1a82b2a265b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_89fe31f6-9eae-4c9b-845e-6e85088675e6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_65fb46ec-72cf-45e0-afc9-a1a82b2a265b" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_89fe31f6-9eae-4c9b-845e-6e85088675e6" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_PerformanceSharesMember" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MarketBasedRestrictedStockUnitsMember_ce6be077-d3fa-4c9b-99a9-8d58d576aaca" xlink:href="amal-20230930.xsd#amal_MarketBasedRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_amal_MarketBasedRestrictedStockUnitsMember_ce6be077-d3fa-4c9b-99a9-8d58d576aaca" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_EmployeeStockMember" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_SeanSearbyMember_bd5ab9c7-decf-46e2-b803-5666b3063fa7" xlink:href="amal-20230930.xsd#amal_SeanSearbyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_amal_SeanSearbyMember_bd5ab9c7-decf-46e2-b803-5666b3063fa7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amal_MandyTennerMember_ac719012-6063-4621-8084-99326e6b914c" xlink:href="amal-20230930.xsd#amal_MandyTennerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_amal_MandyTennerMember_ac719012-6063-4621-8084-99326e6b914c" xlink:type="arc" order="3"/>
  </link:definitionLink>
</link:linkbase>
