<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.6a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByIndustrySector" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByIndustrySector" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByGeographicRegion" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByGeographicRegion" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByCreditQuality" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByCreditQuality" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByMaturity" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByMaturity" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByAssetCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByAssetCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByOtherCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByOtherCategory2" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory2" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#LargestHoldings" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldings" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ProspectusOnly" roleURI="http://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#RiskOnly" roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#CoregistrantOnly" roleURI="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#SeriesOnly" roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ClassOnly" roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#PerformanceMeasureOnly" roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingAssetCategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#BroadBasedIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#AdditionalIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#IndustrySectorOnly" roleURI="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#GeographicRegionOnly" roleURI="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#CreditQualityOnly" roleURI="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#MaturityOnly" roleURI="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#Other1CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#Other2CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#LargestHoldingOnly" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#SalesLoadOnly" roleURI="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ValueMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/ValueMeasureOnly" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#oef_AllRisksMember" xlink:label="loc_oefAllRisksMember" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_ActiveManagementRiskMember" xlink:label="loc_nlfivActiveManagementRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivActiveManagementRiskMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_ADRsRiskMember" xlink:label="loc_nlfivADRsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivADRsRiskMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_DividendPayingStockRiskMember" xlink:label="loc_nlfivDividendPayingStockRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivDividendPayingStockRiskMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_EquitySecuritiesRiskMember" xlink:label="loc_nlfivEquitySecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivEquitySecuritiesRiskMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_ETFInvestmentRiskMember" xlink:label="loc_nlfivETFInvestmentRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivETFInvestmentRiskMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_ETFStructureRiskMember" xlink:label="loc_nlfivETFStructureRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivETFStructureRiskMember" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_NotIndividuallyRedeemableMember" xlink:label="loc_nlfivNotIndividuallyRedeemableMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivNotIndividuallyRedeemableMember" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_TradingIssuesMember" xlink:label="loc_nlfivTradingIssuesMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivTradingIssuesMember" xlink:type="arc" order="70" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_MarketPriceVarianceRiskMember" xlink:label="loc_nlfivMarketPriceVarianceRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivMarketPriceVarianceRiskMember" xlink:type="arc" order="80" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_FluctuationOfNAVRiskMember" xlink:label="loc_nlfivFluctuationOfNAVRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivFluctuationOfNAVRiskMember" xlink:type="arc" order="90" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_IncomeRiskMember" xlink:label="loc_nlfivIncomeRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivIncomeRiskMember" xlink:type="arc" order="100" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_MarketRiskMember" xlink:label="loc_nlfivMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivMarketRiskMember" xlink:type="arc" order="110" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_MidCapMarketRiskMember" xlink:label="loc_nlfivMidCapMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivMidCapMarketRiskMember" xlink:type="arc" order="120" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_SectorExposureRiskMember" xlink:label="loc_nlfivSectorExposureRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivSectorExposureRiskMember" xlink:type="arc" order="130" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_FinancialSectorRiskMember" xlink:label="loc_nlfivFinancialSectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivFinancialSectorRiskMember" xlink:type="arc" order="140" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_GrowthStockRiskMember" xlink:label="loc_nlfivGrowthStockRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivGrowthStockRiskMember" xlink:type="arc" order="150" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_TechnologySectorRiskMember" xlink:label="loc_nlfivTechnologySectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivTechnologySectorRiskMember" xlink:type="arc" order="160" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_ValueRiskMember" xlink:label="loc_nlfivValueRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivValueRiskMember" xlink:type="arc" order="170" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditRiskMember" xlink:label="loc_us-gaapCreditRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_us-gaapCreditRiskMember" xlink:type="arc" order="180" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_FixedIncomeRiskMember" xlink:label="loc_nlfivFixedIncomeRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivFixedIncomeRiskMember" xlink:type="arc" order="190" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateRiskMember" xlink:label="loc_us-gaapInterestRateRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_us-gaapInterestRateRiskMember" xlink:type="arc" order="200" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_USTreasuryObligationsRiskMember" xlink:label="loc_nlfivUSTreasuryObligationsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivUSTreasuryObligationsRiskMember" xlink:type="arc" order="210" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_CashAndCashEquivalentsRiskMember" xlink:label="loc_nlfivCashAndCashEquivalentsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivCashAndCashEquivalentsRiskMember" xlink:type="arc" order="220" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_EmergingMarketsRiskMember" xlink:label="loc_nlfivEmergingMarketsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivEmergingMarketsRiskMember" xlink:type="arc" order="230" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_ForeignSecuritiesRiskMember" xlink:label="loc_nlfivForeignSecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivForeignSecuritiesRiskMember" xlink:type="arc" order="240" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_JunkBondsRiskMember" xlink:label="loc_nlfivJunkBondsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivJunkBondsRiskMember" xlink:type="arc" order="250" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_SmallAndMidCapMarketRiskMember" xlink:label="loc_nlfivSmallAndMidCapMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivSmallAndMidCapMarketRiskMember" xlink:type="arc" order="260" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_LeveragedETFRiskMember" xlink:label="loc_nlfivLeveragedETFRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivLeveragedETFRiskMember" xlink:type="arc" order="270" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_OptionsRiskMember" xlink:label="loc_nlfivOptionsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivOptionsRiskMember" xlink:type="arc" order="280" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_PortfolioTurnoverRiskMember" xlink:label="loc_nlfivPortfolioTurnoverRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_nlfivPortfolioTurnoverRiskMember" xlink:type="arc" order="290" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081761Member" xlink:label="loc_nlfivS000081761Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081761Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081762Member" xlink:label="loc_nlfivS000081762Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081762Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081766Member" xlink:label="loc_nlfivS000081766Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081766Member" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081763Member" xlink:label="loc_nlfivS000081763Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081763Member" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081765Member" xlink:label="loc_nlfivS000081765Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081765Member" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081760Member" xlink:label="loc_nlfivS000081760Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081760Member" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081764Member" xlink:label="loc_nlfivS000081764Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081764Member" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_S000081767Member" xlink:label="loc_nlfivS000081767Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_nlfivS000081767Member" xlink:type="arc" order="70" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#oef_ShareClassDomain" xlink:label="loc_oefShareClassDomain" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244755Member" xlink:label="loc_nlfivC000244755Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244755Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244756Member" xlink:label="loc_nlfivC000244756Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244756Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244760Member" xlink:label="loc_nlfivC000244760Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244760Member" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244757Member" xlink:label="loc_nlfivC000244757Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244757Member" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244759Member" xlink:label="loc_nlfivC000244759Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244759Member" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244754Member" xlink:label="loc_nlfivC000244754Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244754Member" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244758Member" xlink:label="loc_nlfivC000244758Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244758Member" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_C000244761Member" xlink:label="loc_nlfivC000244761Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_nlfivC000244761Member" xlink:type="arc" order="70" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#oef_PerformanceMeasureDomain" xlink:label="loc_oefPerformanceMeasureDomain" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_SAndP500IndexMember" xlink:label="loc_nlfivSAndP500IndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivSAndP500IndexMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_DowJonesUSSelectDividendIndexMember" xlink:label="loc_nlfivDowJonesUSSelectDividendIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivDowJonesUSSelectDividendIndexMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_SAndP500GrowthIndexMember" xlink:label="loc_nlfivSAndP500GrowthIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivSAndP500GrowthIndexMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_DowJonesIndustrialAverage1Member" xlink:label="loc_nlfivDowJonesIndustrialAverage1Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivDowJonesIndustrialAverage1Member" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_SAndP500ValueIndexMember" xlink:label="loc_nlfivSAndP500ValueIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivSAndP500ValueIndexMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_BloombergUSTreasuryBills13MonthsIndexMember" xlink:label="loc_nlfivBloombergUSTreasuryBills13MonthsIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivBloombergUSTreasuryBills13MonthsIndexMember" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_BloombergUSAggregateBondIndexMember" xlink:label="loc_nlfivBloombergUSAggregateBondIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivBloombergUSAggregateBondIndexMember" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_DowJonesModeratePortfolioIndexMember" xlink:label="loc_nlfivDowJonesModeratePortfolioIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivDowJonesModeratePortfolioIndexMember" xlink:type="arc" order="70" />
      <link:loc xlink:type="locator" xlink:href="nlfiv-20260924.xsd#nlfiv_BloombergUSCorporateHighYieldIndexMember" xlink:label="loc_nlfivBloombergUSCorporateHighYieldIndexMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefPerformanceMeasureDomain" xlink:to="loc_nlfivBloombergUSCorporateHighYieldIndexMember" xlink:type="arc" order="80" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ValueMeasureOnly" />
</link:linkbase>
