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Praxikon

Article 4: Definitions

Praxikon tracks Article 4 (Definitions) under the GDPR, alongside the EU AI Act, citing the source for every statement.

Chapter IIn force since 25-05-2018

What does Article 4 govern?

Article 4 sets out the definitions of the 26 terms on which the whole GDPR is built. It determines what personal data are (point 1), what processing is (point 2) and who the controller (point 7) and the processor (point 8) are. Terms such as consent (point 11), personal data breach (point 12) and biometric data (point 14) are also fixed here. The article exists because the rest of the Regulation only works if everyone uses the same words in the same way. Anyone who wants to know whether the GDPR applies to a situation therefore starts here: is the information personal data, and who determines the purposes and means?

Key term: Personal data: any information relating to an identified or identifiable natural person, even where identification is only possible indirectly (point 1)

Directly affects:controllerprocessordata subject

Praxikon’s reading of the text and the recitals; the official text below prevails.

Official text

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For the purposes of this Regulation: (1) ‘personal data’ means any information relating to an identified or identifiable natural person (‘data subject’); an identifiable natural person is one who can be identified, directly or indirectly, in particular by reference to an identifier such as a name, an identification number, location data, an online identifier or to one or more factors specific to the physical, physiological, genetic, mental, economic, cultural or social identity of that natural person; (2) ‘processing’ means any operation or set of operations which is performed on personal data or on sets of personal data, whether or not by automated means, such as collection, recording, organisation, structuring, storage, adaptation or alteration, retrieval, consultation, use, disclosure by transmission, dissemination or otherwise making available, alignment or combination, restriction, erasure or destruction; (3) ‘restriction of processing’ means the marking of stored personal data with the aim of limiting their processing in the future; (4) ‘profiling’ means any form of automated processing of personal data consisting of the use of personal data to evaluate certain personal aspects relating to a natural person, in particular to analyse or predict aspects concerning that natural person's performance at work, economic situation, health, personal preferences, interests, reliability, behaviour, location or movements; (5) ‘pseudonymisation’ means the processing of personal data in such a manner that the personal data can no longer be attributed to a specific data subject without the use of additional information, provided that such additional information is kept separately and is subject to technical and organisational measures to ensure that the personal data are not attributed to an identified or identifiable natural person; (6) ‘filing system’ means any structured set of personal data which are accessible according to specific criteria, whether centralised, decentralised or dispersed on a functional or geographical basis; (7) ‘controller’ means the natural or legal person, public authority, agency or other body which, alone or jointly with others, determines the purposes and means of the processing of personal data; where the purposes and means of such processing are determined by Union or Member State law, the controller or the specific criteria for its nomination may be provided for by Union or Member State law; (8) ‘processor’ means a natural or legal person, public authority, agency or other body which processes personal data on behalf of the controller; (9) ‘recipient’ means a natural or legal person, public authority, agency or another body, to which the personal data are disclosed, whether a third party or not. However, public authorities which may receive personal data in the framework of a particular inquiry in accordance with Union or Member State law shall not be regarded as recipients; the processing of those data by those public authorities shall be in compliance with the applicable data protection rules according to the purposes of the processing; (10) ‘third party’ means a natural or legal person, public authority, agency or body other than the data subject, controller, processor and persons who, under the direct authority of the controller or processor, are authorised to process personal data; (11) ‘consent’ of the data subject means any freely given, specific, informed and unambiguous indication of the data subject's wishes by which he or she, by a statement or by a clear affirmative action, signifies agreement to the processing of personal data relating to him or her; (12) ‘personal data breach’ means a breach of security leading to the accidental or unlawful destruction, loss, alteration, unauthorised disclosure of, or access to, personal data transmitted, stored or otherwise processed; (13) ‘genetic data’ means personal data relating to the inherited or acquired genetic characteristics of a natural person which give unique information about the physiology or the health of that natural person and which result, in particular, from an analysis of a biological sample from the natural person in question; (14) ‘biometric data’ means personal data resulting from specific technical processing relating to the physical, physiological or behavioural characteristics of a natural person, which allow or confirm the unique identification of that natural person, such as facial images or dactyloscopic data; (15) ‘data concerning health’ means personal data related to the physical or mental health of a natural person, including the provision of health care services, which reveal information about his or her health status; (16) ‘main establishment’ means: (a) as regards a controller with establishments in more than one Member State, the place of its central administration in the Union, unless the decisions on the purposes and means of the processing of personal data are taken in another establishment of the controller in the Union and the latter establishment has the power to have such decisions implemented, in which case the establishment having taken such decisions is to be considered to be the main establishment; (b) as regards a processor with establishments in more than one Member State, the place of its central administration in the Union, or, if the processor has no central administration in the Union, the establishment of the processor in the Union where the main processing activities in the context of the activities of an establishment of the processor take place to the extent that the processor is subject to specific obligations under this Regulation; (17) ‘representative’ means a natural or legal person established in the Union who, designated by the controller or processor in writing pursuant to Article 27, represents the controller or processor with regard to their respective obligations under this Regulation; (18) ‘enterprise’ means a natural or legal person engaged in an economic activity, irrespective of its legal form, including partnerships or associations regularly engaged in an economic activity; (19) ‘group of undertakings’ means a controlling undertaking and its controlled undertakings; (20) ‘binding corporate rules’ means personal data protection policies which are adhered to by a controller or processor established on the territory of a Member State for transfers or a set of transfers of personal data to a controller or processor in one or more third countries within a group of undertakings, or group of enterprises engaged in a joint economic activity; (21) ‘supervisory authority’ means an independent public authority which is established by a Member State pursuant to Article 51; (22) ‘supervisory authority concerned’ means a supervisory authority which is concerned by the processing of personal data because: (a) the controller or processor is established on the territory of the Member State of that supervisory authority; (b) data subjects residing in the Member State of that supervisory authority are substantially affected or likely to be substantially affected by the processing; or (c) a complaint has been lodged with that supervisory authority; (23) ‘cross-border processing’ means either: (a) processing of personal data which takes place in the context of the activities of establishments in more than one Member State of a controller or processor in the Union where the controller or processor is established in more than one Member State; or (b) processing of personal data which takes place in the context of the activities of a single establishment of a controller or processor in the Union but which substantially affects or is likely to substantially affect data subjects in more than one Member State. (24) ‘relevant and reasoned objection’ means an objection to a draft decision as to whether there is an infringement of this Regulation, or whether envisaged action in relation to the controller or processor complies with this Regulation, which clearly demonstrates the significance of the risks posed by the draft decision as regards the fundamental rights and freedoms of data subjects and, where applicable, the free flow of personal data within the Union; (25) ‘information society service’ means a service as defined in point (b) of Article 1(1) of Directive (EU) 2015/1535 of the European Parliament and of the Council (19); (26) ‘international organisation’ means an organisation and its subordinate bodies governed by public international law, or any other body which is set up by, or on the basis of, an agreement between two or more countries. CHAPTER II Principles

Source: EUR-Lex, Regulation (EU) 2016/679. Official text, reproduced without modification.

What does this mean for you?

Controller

Establish for each data flow whether it involves personal data within the meaning of point 1; under recital 26 this takes into account all means reasonably likely to be used to identify someone, including an online identifier such as an IP address (recital 30). Determine whether you decide the purposes and means of the processing (point 7), because then you are the controller and the associated obligations rest on you. Record who the recipients (point 9) and third parties (point 10) are, and whether you keep data pseudonymised in line with the requirements of point 5.

Processor

You are a processor if you process personal data on behalf of a controller (point 8) and do not decide the purposes and means yourself. Check that this division of roles matches what you actually do, because as soon as you decide the purposes and means yourself, you become a controller (point 7). In a security incident, the definition in point 12 determines whether there is a personal data breach.

Data Protection Officer

Use the definitions as the test for questions from the organisation: is this personal data or not, is this profiling (point 4), are these biometric or health data (points 14 and 15)? Point out that pseudonymised data remain personal data as long as someone can be re-identified with additional information (point 5 and recital 26).

Data Subject

You are a data subject as soon as information about you can be traced back to you directly or indirectly (point 1). This also covers data that can be linked to you through a name, a number, location data or an online identifier. If an organisation says data are anonymous, nobody may still be able to link them to you by means reasonably likely to be used (recital 26).

Compliance checklist

Related recitals

(23)

In order to ensure that natural persons are not deprived of the protection to which they are entitled under this Regulation, the processing of personal data of data subjects who are in the Union by a ...

(24)

The processing of personal data of data subjects who are in the Union by a controller or processor not established in the Union should also be subject to this Regulation when it is related to the moni...

(25)

Where Member State law applies by virtue of public international law, this Regulation should also apply to a controller not established in the Union, such as in a Member State's diplomatic mission or ...

(26)

The principles of data protection should apply to any information concerning an identified or identifiable natural person. Personal data which have undergone pseudonymisation, which could be attribute...

(27)

This Regulation does not apply to the personal data of deceased persons. Member States may provide for rules regarding the processing of personal data of deceased persons....

(28)

The application of pseudonymisation to personal data can reduce the risks to the data subjects concerned and help controllers and processors to meet their data-protection obligations. The explicit int...

(29)

In order to create incentives to apply pseudonymisation when processing personal data, measures of pseudonymisation should, whilst allowing general analysis, be possible within the same controller whe...

(30)

Natural persons may be associated with online identifiers provided by their devices, applications, tools and protocols, such as internet protocol addresses, cookie identifiers or other identifiers suc...

(31)

Public authorities to which personal data are disclosed in accordance with a legal obligation for the exercise of their official mission, such as tax and customs authorities, financial investigation u...

(32)

Consent should be given by a clear affirmative act establishing a freely given, specific, informed and unambiguous indication of the data subject's agreement to the processing of personal data relatin...

(33)

It is often not possible to fully identify the purpose of personal data processing for scientific research purposes at the time of data collection. Therefore, data subjects should be allowed to give t...

(34)

Genetic data should be defined as personal data relating to the inherited or acquired genetic characteristics of a natural person which result from the analysis of a biological sample from the natural...

(35)

Personal data concerning health should include all data pertaining to the health status of a data subject which reveal information relating to the past, current or future physical or mental health sta...

(36)

The main establishment of a controller in the Union should be the place of its central administration in the Union, unless the decisions on the purposes and means of the processing of personal data ar...

(37)

A group of undertakings should cover a controlling undertaking and its controlled undertakings, whereby the controlling undertaking should be the undertaking which can exert a dominant influence over ...

Cross-references

More case law, guidelines and fines

In addition to the overview at the bottom of this page: rulings, guidelines and fines that interpret or apply this article, newest first. Each item was checked against the official source.

Case law (19)

  • 4 October 2024 · C-200/23 · CJEU
    Agentsia po vpisvaniyata

    A commercial register that publishes personal data is a controller, including for data that were not required. A handwritten signature is personal data, and a brief loss of control over data can be non-material damage.

  • 7 March 2024 · C-479/22 P · CJEURegulation 2018/1725
    OC v Commission

    A press release without a name still contains personal data if the details make the person recognisable to people around her. Decided under Regulation 2018/1725, which uses the same concepts as the GDPR.

  • 7 March 2024 · C-740/22 · CJEU
    Endemol Shine Finland

    Orally disclosing information about criminal proceedings is processing if the information is or will be in a filing system. Such data may not be disclosed to anyone without the requester showing a specific interest.

  • 11 January 2024 · C-231/22 · CJEU
    État belge (Moniteur belge)

    An official journal can be a controller where national law determines the purposes and means of publication. It is then itself responsible for the Article 5 principles, unless national law creates joint responsibility.

  • 5 December 2023 · C-683/21 · CJEU
    Nacionalinis visuomenės sveikatos centras

    Whoever commissions an app and helps decide purposes and means can be a controller without processing data itself. Joint controllership does not require an arrangement between the parties, and a fine requires intent or negligence.

Show 14 more
  • 9 November 2023 · C-319/22 · CJEU
    Gesamtverband Autoteile-Handel

    A vehicle identification number is personal data for anyone who reasonably has the means to link it to the keeper. Manufacturers have a legal obligation to make these numbers available to independent repairers.

  • 27 October 2022 · C-129/21 · CJEU
    Proximus

    Inclusion in public telephone directories requires consent within the meaning of the GDPR. A request to be removed from directories is an exercise of the right to erasure, and the directory provider must take reasonable steps to inform other providers and search engines.

  • 11 November 2020 · C-61/19 · CJEU
    Orange Romania

    The controller must show that the data subject gave active and informed consent. A box ticked by the seller in a contract does not prove that.

  • 9 July 2020 · C-272/19 · CJEU
    VQ v Land Hessen (petitions committee)

    The petitions committee of a regional parliament that determines purposes and means is a controller and falls under the GDPR, including the right of access.

  • 1 October 2019 · C-673/17 · CJEU
    Planet49

    A pre-ticked checkbox does not give valid consent for cookies. Users must also be told how long cookies operate and whether third parties can access them.

  • 29 July 2019 · C-40/17 · CJEUDirective 95/46
    Fashion ID

    A website embedding a Facebook button is a joint controller, but only for collecting and transmitting visitor data. Consumer associations may bring proceedings on behalf of data subjects.

  • 10 July 2018 · C-25/17 · CJEUDirective 95/46
    Jehovan todistajat

    Notes taken by members of a religious community during door-to-door preaching are not a household activity and can form a filing system. The community is a joint controller with its members, even without access to the data itself.

  • 5 June 2018 · C-210/16 · CJEUDirective 95/46
    Wirtschaftsakademie

    The administrator of a Facebook fan page is a controller together with Facebook. A Member State's supervisory authority may act against the group's establishment on its territory.

  • 20 December 2017 · C-434/16 · CJEUDirective 95/46
    Nowak

    A candidate's written exam answers and the examiner's comments on them are personal data of the candidate.

  • 19 October 2016 · C-582/14 · CJEUDirective 95/46
    Breyer

    A dynamic IP address is personal data for a website operator that has legal means to have the user identified through the internet service provider. National law may not exclude the legitimate interests basis in advance.

  • 17 July 2014 · C-141/12, C-372/12 · CJEUDirective 95/46
    YS and Others

    The data about an applicant in an internal memo are personal data, but the legal analysis itself is not. For access, a full and intelligible summary of the data is enough; a copy of the document is not required.

  • 13 May 2014 · C-131/12 · CJEUDirective 95/46
    Google Spain

    A search engine processes personal data as a controller and falls under EU law through a sales establishment in a Member State. Data subjects can ask for results on their name to be removed, the origin of the right to be forgotten.

  • 24 November 2011 · C-70/10 · CJEUDirective 95/46
    Scarlet Extended

    An internet service provider cannot be required to filter all traffic preventively. The Court states that IP addresses are protected personal data because they allow users to be precisely identified.

  • 6 November 2003 · C-101/01 · CJEUDirective 95/46
    Lindqvist

    Naming people on a web page is automated processing that falls outside the household exemption; a foot injury is health data, and uploading to an EU-hosted site is not a transfer to a third country.

Guidelines and decisions (6)

Show 1 more
  • 20 June 2007 · WP136 (Opinion 4/2007) · Article 29 Working PartyDirective 95/46
    Opinion 4/2007 on the concept of personal data

    Breaks the concept of personal data down into its elements and gives examples of when information relates to an identifiable person.

Line of case lawWhat is personal data?

When does information relate to an identifiable person?

  1. Lindqvist (2003)A name with job or hobby on a web page is personal data.
  2. YS and Others (2014)The legal analysis in a file is not personal data itself, the data in it are.
  3. Breyer (2016)A dynamic IP address counts if you have legal means to have the user identified.
  4. Nowak (2017)Exam answers and examiner comments are personal data of the candidate.
  5. Gesamtverband Autoteile-Handel (2023)A vehicle number is personal data for anyone who can reasonably link it to the keeper.
  6. OC v Commission (2024)Even without a name, details can make a person recognisable.
  7. IAB Europe (2024)A consent string becomes personal data once it can reasonably be linked to a user.
  8. EDPS v SRB (2025)Pseudonymised data are not personal data for every recipient.
  9. Digital Omnibus: proposal amending the GDPR (2025)Proposal to write that relative approach into Article 4.
Line of case lawAnonymisation and pseudonymisation

When do data fall outside the GDPR?

  1. Opinion 05/2014 on Anonymisation Techniques (2014)The Article 29 Working Party tests anonymisation techniques against singling out, linkability and inference.
  2. Breyer (2016)Only means reasonably likely to be used count for identifiability.
  3. Opinion 28/2024 on certain data protection aspects related to the processing of personal data in the context of AI models (2024)An AI model trained on personal data is not anonymous by default.
  4. Guidelines 01/2025 on Pseudonymisation (2025)Pseudonymised data remain personal data; pseudonymisation does lower the risk.
  5. EDPS v SRB (2025)The Court adopts a relative approach from the recipient's side.
  6. Digital Omnibus: proposal amending the GDPR (2025)Proposal to write the relative approach into the law.
  7. Guidelines 02/2026 on Anonymisation (2026)New EDPB guidelines on anonymisation, under consultation.
Line of case lawWho is the controller?

When are you a (joint) controller?

  1. Google Spain (2014)A search engine is responsible for its own processing of others' publications.
  2. Wirtschaftsakademie (2018)A fan page administrator is responsible together with Facebook.
  3. Jehovan todistajat (2018)An organisation steering processing is jointly responsible, even without access to the data.
  4. Fashion ID (2019)Joint responsibility applies per stage of processing.
  5. Guidelines 07/2020 on the concepts of controller and processor in the GDPR (2021)The EDPB sets out the criteria for controller and processor.
  6. Nacionalinis visuomenės sveikatos centras (2023)Whoever commissions an app and sets its purposes is responsible without processing data itself.
  7. IAB Europe (2024)An industry body imposing a standard can be jointly responsible.
  8. Russmedia Digital (2025)An online marketplace is responsible for personal data in advertisements.
Line of case lawConsent and cookies

When is consent valid?

  1. Planet49 (2019)A pre-ticked box is not consent.
  2. Guidelines 05/2020 on consent under Regulation 2016/679 (2020)The EDPB: cookie walls and scrolling do not give valid consent.
  3. Orange Romania (2020)The controller must prove consent.
  4. Meta Platforms v Bundeskartellamt (2023)A dominant position does not rule out consent but weighs heavily.
  5. Opinion 08/2024 on Valid Consent in the Context of Consent or Pay Models Implemented by Large Online Platforms (2024)Pay or consent on large platforms is usually not a free choice.
  6. Inteligo Media (2025)Within the ePrivacy soft opt-in no separate GDPR basis is needed.
  7. Digital Omnibus: proposal amending the GDPR (2025)Proposal to move cookie rules into the GDPR.

Checked on 5 November 2026

Frequently asked questions

Connections

What connects to Article 4 GDPR

Themes where this returns

Where this meets the other law

The counterpart in the other law

Case law8 of 9

Guidelines

Enforcement and fines

Legislation in motion6 of 8

Analysis