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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a0682c-4c1c-70af-96f7-a908c011de84,g:f77c4206-dc3a-43a4-aee4-dae9c96fd39d-->
<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://fhlb.com/role/Cover" xlink:type="simple" xlink:href="fhlbd-20260831.xsd#Cover"/>
  <link:definitionLink xlink:role="http://fhlb.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_01a0682c-4c1c-79f3-96f2-74174febd73f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntitiesTable_01a0682c-4c1c-79f3-96f2-74174febd73f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_01a0682c-4c1c-712b-b009-c01ddd085c95" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_01a0682c-4c1c-79f3-96f2-74174febd73f" xlink:to="loc_dei_LegalEntityAxis_01a0682c-4c1c-712b-b009-c01ddd085c95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a0682c-4c1c-712b-b009-c01ddd085c95_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_01a0682c-4c1c-712b-b009-c01ddd085c95" xlink:to="loc_dei_EntityDomain_01a0682c-4c1c-712b-b009-c01ddd085c95_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a0682c-4c1c-7f5d-8102-05d539706dec" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_01a0682c-4c1c-712b-b009-c01ddd085c95" xlink:to="loc_dei_EntityDomain_01a0682c-4c1c-7f5d-8102-05d539706dec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a0682c-4c1c-7be5-b079-442fa857337b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_AmendmentFlag_01a0682c-4c1c-7be5-b079-442fa857337b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a0682c-4c1c-73c9-9e35-4c5bfa4eb92f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_DocumentType_01a0682c-4c1c-73c9-9e35-4c5bfa4eb92f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a0682c-4c1c-75dc-a829-e64a5b3d8def" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_DocumentPeriodEndDate_01a0682c-4c1c-75dc-a829-e64a5b3d8def" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a0682c-4c1c-72fa-ac77-b1a7393a2dac" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityRegistrantName_01a0682c-4c1c-72fa-ac77-b1a7393a2dac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a0682c-4c1c-7724-933e-386357fb60ed" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityCentralIndexKey_01a0682c-4c1c-7724-933e-386357fb60ed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a0682c-4c1c-7667-8fbc-159162e06a44" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityFileNumber_01a0682c-4c1c-7667-8fbc-159162e06a44" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a0682c-4c1c-79e5-967f-c1377578b30f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a0682c-4c1c-79e5-967f-c1377578b30f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a0682c-4c1c-7e4c-ac8b-b22cf14d2f7a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityAddressAddressLine1_01a0682c-4c1c-7e4c-ac8b-b22cf14d2f7a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a0682c-4c1c-7d60-b5e9-a42e45f691b1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityAddressCityOrTown_01a0682c-4c1c-7d60-b5e9-a42e45f691b1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_01a0682c-4c1c-705a-9c80-7a7d28ed5bf8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityAddressStateOrProvince_01a0682c-4c1c-705a-9c80-7a7d28ed5bf8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a0682c-4c1c-752e-8e7e-9afc6401f130" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityAddressPostalZipCode_01a0682c-4c1c-752e-8e7e-9afc6401f130" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a0682c-4c1c-76a0-9f2c-b706faae71e0" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_CityAreaCode_01a0682c-4c1c-76a0-9f2c-b706faae71e0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a0682c-4c1c-7408-a3ab-2b80c9608e2e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_LocalPhoneNumber_01a0682c-4c1c-7408-a3ab-2b80c9608e2e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a0682c-4c1c-746a-ba8a-17d3cd030c5e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_WrittenCommunications_01a0682c-4c1c-746a-ba8a-17d3cd030c5e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a0682c-4c1c-74be-8959-5a29b879c90b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_SolicitingMaterial_01a0682c-4c1c-74be-8959-5a29b879c90b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a0682c-4c1c-737e-8103-51a421acdd5a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_PreCommencementTenderOffer_01a0682c-4c1c-737e-8103-51a421acdd5a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a0682c-4c1c-7e29-ab3b-a22ef6f41850" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a0682c-4c1c-7e29-ab3b-a22ef6f41850" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a0682c-4c1c-71eb-85b8-b031151f8e3a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a0682c-4c1c-71eb-85b8-b031151f8e3a" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a0682c-4c1c-7384-a515-29335ac31de1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_01a0682c-4c1c-7deb-b969-501e17fd00ca" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a0682c-4c1c-7384-a515-29335ac31de1" xlink:type="arc" order="18"/>
  </link:definitionLink>
</link:linkbase>
