> For the complete documentation index, see [llms.txt](https://www.headlesslaw.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.headlesslaw.com/definitions/readme.md).

# Definitions

Canonical, cross-linked EU regulation definitions, grouped by the rulebook that defines them (AI Act, MiFID II, DORA, AMLR, MiFIR, CRA, MiCA, Data Act, NIS2, MAR, GDPR, DSA, ToFR, ePrivacy, PSD2, AIFM

EU law defines its own vocabulary, and the definitions differ between acts. Browse every defined term, see where it applies, and follow it across regulations.

Definitions are derived artifacts, regenerated from the primary legal-text corpus. Where more than one rulebook defines a term, every regime-scoped variant is kept — the cross-rulebook collision index and article-scoped usage indexes are exposed under `/api/definitions/index.json` and `/api/rulebooks/:law/article-definitions.json`.

### By rulebook

636 definitions across 20 rulebooks. Browse a rulebook's full set below, or start from a specific term via the sidebar.

* [**AI Act Definitions**](/definitions/ai-act.md) — 70 terms · AI Act Article 3
* [**MiFID II Definitions**](/definitions/mifid-ii.md) — 66 terms · MiFID II Article 4 and Annex II
* [**DORA Definitions**](/definitions/dora.md) — 65 terms · DORA Article 3
* [**AMLR Definitions**](/definitions/amlr.md) — 57 terms · AMLR Article 2
* [**MiFIR Definitions**](/definitions/mifir.md) — 57 terms · MiFIR Article 2
* [**CRA Definitions**](/definitions/cra.md) — 51 terms · CRA Article 3
* [**MiCA Definitions**](/definitions/mica.md) — 51 terms · MiCA Article 3
* [**Data Act Definitions**](/definitions/data-act.md) — 43 terms · Data Act Article 2
* [**NIS2 Definitions**](/definitions/nis2.md) — 41 terms · NIS2 Article 6
* [**MAR Definitions**](/definitions/mar.md) — 40 terms · MAR Article 3
* [**GDPR Definitions**](/definitions/gdpr.md) — 26 terms · GDPR Article 4
* [**DSA Definitions**](/definitions/dsa.md) — 24 terms · DSA Article 3
* [**ToFR Definitions**](/definitions/tofr.md) — 24 terms · ToFR Article 3
* [**ePrivacy Definitions**](/definitions/eprivacy.md) — 9 terms · ePrivacy Article 2
* [**PSD2 Definitions**](/definitions/psd2.md) — 4 terms · PSD2 Article 4 and Annex I
* [**AIFMD Definitions**](/definitions/aifmd.md) — 2 terms · AIFMD Article 4
* [**CRR Definitions**](/definitions/crr.md) — 2 terms · CRR Article 4
* [**EMD2 Definitions**](/definitions/emd2.md) — 2 terms · EMD2 Article 2
* [**DGSD Definitions**](/definitions/dgsd.md) — 1 term · DGSD Article 2
* [**UCITS Definitions**](/definitions/ucits.md) — 1 term · UCITS Article 2

### Defined in more than one rulebook

Terms whose meaning is set by several rulebooks. Each links to every regime-scoped variant so you can compare the wording side by side.

* **agricultural commodity derivatives** — [MiFID II](/definitions/mifid-ii/agricultural-commodity-derivatives.md) · [MiFIR](/definitions/mifir/agricultural-commodity-derivatives.md)
* **algorithmic trading** — [MiFID II](/definitions/mifid-ii/algorithmic-trading.md) · [MAR](/definitions/mar/algorithmic-trading.md)
* **alternative investment fund manager** — [MiCA](/definitions/mica/alternative-investment-fund-manager.md) · [AIFMD](/definitions/aifmd/alternative-investment-fund-manager.md)
* **ancillary services** — [MiFID II](/definitions/mifid-ii/ancillary-services.md) · [MiFIR](/definitions/mifir/ancillary-services.md)
* **authorised representative** — [AI Act](/definitions/ai-act/authorised-representative.md) · [CRA](/definitions/cra/authorised-representative.md)
* **benchmark** — [MiFIR](/definitions/mifir/benchmark.md) · [MAR](/definitions/mar/benchmark.md)
* **biometric data** — [AI Act](/definitions/ai-act/biometric-data.md) · [GDPR](/definitions/gdpr/biometric-data.md)
* **branch** — [MiFID II](/definitions/mifid-ii/branch.md) · [MiFIR](/definitions/mifir/branch.md)
* **CCP** — [MiFID II](/definitions/mifid-ii/ccp.md) · [MiFIR](/definitions/mifir/ccp.md)
* **CE marking** — [AI Act](/definitions/ai-act/ce-marking.md) · [CRA](/definitions/cra/ce-marking.md)
* **central securities depository** — [MiFID II](/definitions/mifid-ii/central-securities-depository.md) · [DORA](/definitions/dora/central-securities-depository.md)
* **certificates** — [MiFID II](/definitions/mifid-ii/certificates.md) · [MiFIR](/definitions/mifir/certificates.md)
* **client** — [MiFID II](/definitions/mifid-ii/client.md) · [MiFIR](/definitions/mifir/client.md) · [MiCA](/definitions/mica/client.md)
* **close links** — [MiFID II](/definitions/mifid-ii/close-links.md) · [MiFIR](/definitions/mifir/close-links.md) · [MiCA](/definitions/mica/close-links.md)
* **commodity derivatives** — [MiFID II](/definitions/mifid-ii/commodity-derivatives.md) · [MiFIR](/definitions/mifir/commodity-derivatives.md) · [MAR](/definitions/mar/commodity-derivatives.md)
* **competent authority** — [MiFID II](/definitions/mifid-ii/competent-authority.md) · [AMLR](/definitions/amlr/competent-authority.md) · [MiFIR](/definitions/mifir/competent-authority.md) · [MiCA](/definitions/mica/competent-authority.md) · [MAR](/definitions/mar/competent-authority.md)
* **conformity assessment** — [AI Act](/definitions/ai-act/conformity-assessment.md) · [CRA](/definitions/cra/conformity-assessment.md)
* **conformity assessment body** — [AI Act](/definitions/ai-act/conformity-assessment-body.md) · [CRA](/definitions/cra/conformity-assessment-body.md)
* **consumer** — [CRA](/definitions/cra/consumer.md) · [Data Act](/definitions/data-act/consumer.md) · [DSA](/definitions/dsa/consumer.md)
* **credit institution** — [MiFID II](/definitions/mifid-ii/credit-institution.md) · [DORA](/definitions/dora/credit-institution.md) · [AMLR](/definitions/amlr/credit-institution.md) · [MiFIR](/definitions/mifir/credit-institution.md) · [MiCA](/definitions/mica/credit-institution.md) · [MAR](/definitions/mar/credit-institution.md) · [CRR](/definitions/crr/credit-institution.md)
* **crowdfunding service provider** — [DORA](/definitions/dora/crowdfunding-service-provider.md) · [AMLR](/definitions/amlr/crowdfunding-service-provider.md)
* **crypto-asset** — [AMLR](/definitions/amlr/crypto-asset.md) · [MiCA](/definitions/mica/crypto-asset.md) · [ToFR](/definitions/tofr/crypto-asset.md)
* **crypto-asset account** — [AMLR](/definitions/amlr/crypto-asset-account.md) · [ToFR](/definitions/tofr/crypto-asset-account.md)
* **crypto-asset service provider** — [DORA](/definitions/dora/crypto-asset-service-provider.md) · [AMLR](/definitions/amlr/crypto-asset-service-provider.md) · [MiCA](/definitions/mica/crypto-asset-service-provider.md) · [ToFR](/definitions/tofr/crypto-asset-service-provider.md)
* **cyber threat** — [DORA](/definitions/dora/cyber-threat.md) · [CRA](/definitions/cra/cyber-threat.md) · [NIS2](/definitions/nis2/cyber-threat.md)
* **cybersecurity** — [CRA](/definitions/cra/cybersecurity.md) · [NIS2](/definitions/nis2/cybersecurity.md)
* **dealing on own account** — [MiFID II](/definitions/mifid-ii/dealing-on-own-account.md) · [MiFIR](/definitions/mifir/dealing-on-own-account.md)
* **deposit** — [MiCA](/definitions/mica/deposit.md) · [DGSD](/definitions/dgsd/deposit.md)
* **depositary receipts** — [MiFID II](/definitions/mifid-ii/depositary-receipts.md) · [MiFIR](/definitions/mifir/depositary-receipts.md)
* **derivatives** — [MiFID II](/definitions/mifid-ii/derivatives.md) · [MiFIR](/definitions/mifir/derivatives.md)
* **distributed ledger technology** — [MiCA](/definitions/mica/distributed-ledger-technology.md) · [ToFR](/definitions/tofr/distributed-ledger-technology.md)
* **distributor** — [AI Act](/definitions/ai-act/distributor.md) · [CRA](/definitions/cra/distributor.md)
* **electronic money** — [AMLR](/definitions/amlr/electronic-money.md) · [MiCA](/definitions/mica/electronic-money.md) · [EMD2](/definitions/emd2/electronic-money.md)
* **electronic money institution** — [DORA](/definitions/dora/electronic-money-institution.md) · [MiCA](/definitions/mica/electronic-money-institution.md) · [EMD2](/definitions/emd2/electronic-money-institution.md)
* **enterprise** — [Data Act](/definitions/data-act/enterprise.md) · [GDPR](/definitions/gdpr/enterprise.md)
* **exchange-traded fund** — [MiFID II](/definitions/mifid-ii/exchange-traded-fund.md) · [MiFIR](/definitions/mifir/exchange-traded-fund.md)
* **execution of orders on behalf of clients** — [MiFID II](/definitions/mifid-ii/execution-of-orders-on-behalf-of-clients.md) · [MiFIR](/definitions/mifir/execution-of-orders-on-behalf-of-clients.md)
* **financial institution** — [AMLR](/definitions/amlr/financial-institution.md) · [MAR](/definitions/mar/financial-institution.md)
* **financial instrument** — [MiFID II](/definitions/mifid-ii/financial-instrument.md) · [MiFIR](/definitions/mifir/financial-instrument.md) · [MiCA](/definitions/mica/financial-instrument.md) · [MAR](/definitions/mar/financial-instrument.md)
* **funds** — [AMLR](/definitions/amlr/funds.md) · [MiCA](/definitions/mica/funds.md) · [ToFR](/definitions/tofr/funds.md) · [PSD2](/definitions/psd2/funds.md)
* **group** — [MiFID II](/definitions/mifid-ii/group.md) · [DORA](/definitions/dora/group.md) · [AMLR](/definitions/amlr/group.md)
* **harmonised standard** — [AI Act](/definitions/ai-act/harmonised-standard.md) · [CRA](/definitions/cra/harmonised-standard.md) · [Data Act](/definitions/data-act/harmonised-standard.md)
* **home Member State** — [MiFID II](/definitions/mifid-ii/home-member-state.md) · [MiFIR](/definitions/mifir/home-member-state.md) · [MiCA](/definitions/mica/home-member-state.md)
* **host Member State** — [MiFID II](/definitions/mifid-ii/host-member-state.md) · [MiFIR](/definitions/mifir/host-member-state.md) · [MiCA](/definitions/mica/host-member-state.md)
* **importer** — [AI Act](/definitions/ai-act/importer.md) · [CRA](/definitions/cra/importer.md)
* **incident** — [CRA](/definitions/cra/incident.md) · [NIS2](/definitions/nis2/incident.md)
* **information society service** — [GDPR](/definitions/gdpr/information-society-service.md) · [DSA](/definitions/dsa/information-society-service.md)
* **intended purpose** — [AI Act](/definitions/ai-act/intended-purpose.md) · [CRA](/definitions/cra/intended-purpose.md)
* **investment firm** — [MiFID II](/definitions/mifid-ii/investment-firm.md) · [DORA](/definitions/dora/investment-firm.md) · [MiFIR](/definitions/mifir/investment-firm.md) · [MiCA](/definitions/mica/investment-firm.md) · [MAR](/definitions/mar/investment-firm.md) · [CRR](/definitions/crr/investment-firm.md)
* **investment services and activities** — [MiFID II](/definitions/mifid-ii/investment-services-and-activities.md) · [MiFIR](/definitions/mifir/investment-services-and-activities.md)
* **issuer** — [MiCA](/definitions/mica/issuer.md) · [MAR](/definitions/mar/issuer.md)
* **Legal Entity Identifier** — [AMLR](/definitions/amlr/legal-entity-identifier.md) · [ToFR](/definitions/tofr/legal-entity-identifier.md)
* **liquid market** — [MiFID II](/definitions/mifid-ii/liquid-market.md) · [MiFIR](/definitions/mifir/liquid-market.md)
* **making available on the market** — [AI Act](/definitions/ai-act/making-available-on-the-market.md) · [CRA](/definitions/cra/making-available-on-the-market.md) · [Data Act](/definitions/data-act/making-available-on-the-market.md)
* **management body** — [MiFID II](/definitions/mifid-ii/management-body.md) · [DORA](/definitions/dora/management-body.md) · [AMLR](/definitions/amlr/management-body.md) · [MiFIR](/definitions/mifir/management-body.md) · [MiCA](/definitions/mica/management-body.md)
* **management company** — [DORA](/definitions/dora/management-company.md) · [UCITS](/definitions/ucits/management-company.md)
* **market maker** — [MiFID II](/definitions/mifid-ii/market-maker.md) · [MiFIR](/definitions/mifir/market-maker.md) · [MAR](/definitions/mar/market-maker.md)
* **market operator** — [MiFID II](/definitions/mifid-ii/market-operator.md) · [MiFIR](/definitions/mifir/market-operator.md) · [MAR](/definitions/mar/market-operator.md)
* **market surveillance authority** — [AI Act](/definitions/ai-act/market-surveillance-authority.md) · [CRA](/definitions/cra/market-surveillance-authority.md)
* **matched principal trading** — [MiFID II](/definitions/mifid-ii/matched-principal-trading.md) · [MiCA](/definitions/mica/matched-principal-trading.md)
* **microenterprise** — [DORA](/definitions/dora/microenterprise.md) · [Data Act](/definitions/data-act/microenterprise.md)
* **money laundering** — [AMLR](/definitions/amlr/money-laundering.md) · [ToFR](/definitions/tofr/money-laundering.md)
* **multilateral system** — [MiFID II](/definitions/mifid-ii/multilateral-system.md) · [MiFIR](/definitions/mifir/multilateral-system.md)
* **multilateral trading facility** — [MiFID II](/definitions/mifid-ii/multilateral-trading-facility.md) · [MiFIR](/definitions/mifir/multilateral-trading-facility.md) · [MAR](/definitions/mar/multilateral-trading-facility.md)
* **near miss** — [CRA](/definitions/cra/near-miss.md) · [NIS2](/definitions/nis2/near-miss.md)
* **network and information system** — [DORA](/definitions/dora/network-and-information-system.md) · [NIS2](/definitions/nis2/network-and-information-system.md)
* **non-personal data** — [AI Act](/definitions/ai-act/non-personal-data.md) · [Data Act](/definitions/data-act/non-personal-data.md)
* **notified body** — [AI Act](/definitions/ai-act/notified-body.md) · [CRA](/definitions/cra/notified-body.md)
* **notifying authority** — [AI Act](/definitions/ai-act/notifying-authority.md) · [CRA](/definitions/cra/notifying-authority.md)
* **online interface** — [MiCA](/definitions/mica/online-interface.md) · [DSA](/definitions/dsa/online-interface.md)
* **online search engine** — [NIS2](/definitions/nis2/online-search-engine.md) · [DSA](/definitions/dsa/online-search-engine.md)
* **organised trading facility** — [MiFID II](/definitions/mifid-ii/organised-trading-facility.md) · [MiFIR](/definitions/mifir/organised-trading-facility.md) · [MAR](/definitions/mar/organised-trading-facility.md)
* **parent undertaking** — [MiFID II](/definitions/mifid-ii/parent-undertaking.md) · [DORA](/definitions/dora/parent-undertaking.md) · [AMLR](/definitions/amlr/parent-undertaking.md)
* **payment institution** — [DORA](/definitions/dora/payment-institution.md) · [MiCA](/definitions/mica/payment-institution.md) · [PSD2](/definitions/psd2/payment-institution.md)
* **payment service provider** — [MiCA](/definitions/mica/payment-service-provider.md) · [ToFR](/definitions/tofr/payment-service-provider.md) · [PSD2](/definitions/psd2/payment-service-provider.md)
* **payment services** — [MiCA](/definitions/mica/payment-services.md) · [PSD2](/definitions/psd2/payment-services.md)
* **personal data** — [AI Act](/definitions/ai-act/personal-data.md) · [CRA](/definitions/cra/personal-data.md) · [MiCA](/definitions/mica/personal-data.md) · [Data Act](/definitions/data-act/personal-data.md) · [GDPR](/definitions/gdpr/personal-data.md)
* **personal data breach** — [GDPR](/definitions/gdpr/personal-data-breach.md) · [ePrivacy](/definitions/eprivacy/personal-data-breach.md)
* **placing on the market** — [AI Act](/definitions/ai-act/placing-on-the-market.md) · [CRA](/definitions/cra/placing-on-the-market.md) · [Data Act](/definitions/data-act/placing-on-the-market.md)
* **processing** — [Data Act](/definitions/data-act/processing.md) · [GDPR](/definitions/gdpr/processing.md)
* **professional client** — [MiFID II](/definitions/mifid-ii/professional-client.md) · [MiFIR](/definitions/mifir/professional-client.md)
* **profiling** — [AI Act](/definitions/ai-act/profiling.md) · [Data Act](/definitions/data-act/profiling.md) · [GDPR](/definitions/gdpr/profiling.md)
* **qualified investors** — [MiFID II](/definitions/mifid-ii/qualified-investors.md) · [MiCA](/definitions/mica/qualified-investors.md)
* **qualifying holding** — [MiFID II](/definitions/mifid-ii/qualifying-holding.md) · [MiCA](/definitions/mica/qualifying-holding.md)
* **reasonably foreseeable misuse** — [AI Act](/definitions/ai-act/reasonably-foreseeable-misuse.md) · [CRA](/definitions/cra/reasonably-foreseeable-misuse.md)
* **regulated market** — [MiFID II](/definitions/mifid-ii/regulated-market.md) · [MiFIR](/definitions/mifir/regulated-market.md) · [MAR](/definitions/mar/regulated-market.md)
* **representative** — [NIS2](/definitions/nis2/representative.md) · [GDPR](/definitions/gdpr/representative.md)
* **risk** — [AI Act](/definitions/ai-act/risk.md) · [NIS2](/definitions/nis2/risk.md)
* **security of network and information systems** — [DORA](/definitions/dora/security-of-network-and-information-systems.md) · [NIS2](/definitions/nis2/security-of-network-and-information-systems.md)
* **self-hosted address** — [AMLR](/definitions/amlr/self-hosted-address.md) · [ToFR](/definitions/tofr/self-hosted-address.md)
* **senior management** — [MiFID II](/definitions/mifid-ii/senior-management.md) · [AMLR](/definitions/amlr/senior-management.md) · [MiFIR](/definitions/mifir/senior-management.md)
* **significant cyber threat** — [DORA](/definitions/dora/significant-cyber-threat.md) · [NIS2](/definitions/nis2/significant-cyber-threat.md)
* **small enterprise** — [DORA](/definitions/dora/small-enterprise.md) · [Data Act](/definitions/data-act/small-enterprise.md)
* **SME growth market** — [MiFID II](/definitions/mifid-ii/sme-growth-market.md) · [MiFIR](/definitions/mifir/sme-growth-market.md) · [MAR](/definitions/mar/sme-growth-market.md)
* **sovereign debt** — [MiFID II](/definitions/mifid-ii/sovereign-debt.md) · [MiFIR](/definitions/mifir/sovereign-debt.md)
* **structured deposit** — [MiFID II](/definitions/mifid-ii/structured-deposit.md) · [MiFIR](/definitions/mifir/structured-deposit.md) · [MiCA](/definitions/mica/structured-deposit.md)
* **structured finance products** — [MiFID II](/definitions/mifid-ii/structured-finance-products.md) · [MiFIR](/definitions/mifir/structured-finance-products.md)
* **subsidiary** — [MiFID II](/definitions/mifid-ii/subsidiary.md) · [DORA](/definitions/dora/subsidiary.md)
* **substantial modification** — [AI Act](/definitions/ai-act/substantial-modification.md) · [CRA](/definitions/cra/substantial-modification.md)
* **supervisory authority** — [AMLR](/definitions/amlr/supervisory-authority.md) · [GDPR](/definitions/gdpr/supervisory-authority.md)
* **systematic internaliser** — [MiFID II](/definitions/mifid-ii/systematic-internaliser.md) · [MiFIR](/definitions/mifir/systematic-internaliser.md) · [MAR](/definitions/mar/systematic-internaliser.md)
* **terrorist financing** — [AMLR](/definitions/amlr/terrorist-financing.md) · [ToFR](/definitions/tofr/terrorist-financing.md)
* **third-country firm** — [MiFID II](/definitions/mifid-ii/third-country-firm.md) · [MiFIR](/definitions/mifir/third-country-firm.md)
* **trading venue** — [MiFID II](/definitions/mifid-ii/trading-venue.md) · [DORA](/definitions/dora/trading-venue.md) · [MiFIR](/definitions/mifir/trading-venue.md) · [MAR](/definitions/mar/trading-venue.md)
* **transferable securities** — [MiFID II](/definitions/mifid-ii/transferable-securities.md) · [MiFIR](/definitions/mifir/transferable-securities.md)
* **UCITS management company** — [MiFID II](/definitions/mifid-ii/ucits-management-company.md) · [MiCA](/definitions/mica/ucits-management-company.md)
* **user** — [Data Act](/definitions/data-act/user.md) · [ePrivacy](/definitions/eprivacy/user.md)
* **vulnerability** — [DORA](/definitions/dora/vulnerability.md) · [CRA](/definitions/cra/vulnerability.md) · [NIS2](/definitions/nis2/vulnerability.md)
* **wholesale energy product** — [MiFID II](/definitions/mifid-ii/wholesale-energy-product.md) · [MiFIR](/definitions/mifir/wholesale-energy-product.md) · [MAR](/definitions/mar/wholesale-energy-product.md)


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