Official Sync:2026-04-28

Glossário A–Z — Acessibilidade digital em Portugal

Definições verificadas dos termos do Decreto-Lei n.º 82/2022 e da Diretiva (UE) 2019/882, com referências ao Diário da República e a EUR-Lex. Inclui terminologia das autoridades de fiscalização portuguesas (INR, I. P.; ANACOM; ASAE; Banco de Portugal; CMVM).

Última atualização: 28 de abril de 2026

A

Accessibility Tree: A hierarchical representation of the accessible objects in a user interface, built from the DOM and CSS by the browser and exposed to assistive technologies via platform accessibility APIs. It contains each element's accessible name, role, state, and properties.
Accessible Description: Additional information associated with a UI element that supplements its accessible name. Exposed via aria-describedby or similar mechanisms and announced by screen readers after the name.
Accessible Name: The label that identifies a UI element to assistive technologies, computed using the accessible name and description computation algorithm. Defined in WCAG 2.2 SC 4.1.2 and ARIA specifications.
Accessible Rich Internet Applications: See ARIA. A W3C specification that provides a set of roles, states, and properties to make dynamic web content accessible to users of assistive technologies.
Acessibilidade Digital: Conjunto de princípios e práticas que garantem que produtos e serviços digitais — sítios Web, aplicações móveis, documentos eletrónicos, terminais e equipamentos informáticos — possam ser percecionados, utilizados e compreendidos por pessoas com deficiência. Em Portugal, é regulada pelo Decreto-Lei n.º 82/2022 (setor privado, transposição da Diretiva (UE) 2019/882) e pelo Decreto-Lei n.º 83/2018 (setor público).
ACR: Accessibility Conformance Report. A document that explains how a product or service conforms to accessibility standards like WCAG or Section 508. Generated using a VPAT template.
ADA: Americans with Disabilities Act. A US civil rights law that prohibits discrimination against individuals with disabilities in all areas of public life, including digital services.
Advisory Technique: A recommended but optional method for meeting a WCAG success criterion that goes beyond what is strictly required. Advisory techniques improve accessibility but are not needed for conformance.
AEO: Answer Engine Optimization. The practice of optimizing content to be accurately understood and retrieved by AI-powered search and answer engines.
Alt Text: Short for 'alternative text'. Descriptive text assigned to an image via the HTML alt attribute so that screen readers can convey the image content to users who cannot see it. Required by WCAG 2.2 SC 1.1.1.
ANACOM: Autoridade Nacional de Comunicações. Entidade reguladora do setor das comunicações eletrónicas e dos serviços postais em Portugal. Atua como autoridade competente para a fiscalização da acessibilidade dos serviços de comunicações eletrónicas e dos números 112 abrangidos pelo Decreto-Lei n.º 82/2022.
Anexo I (Diretiva 2019/882): Anexo da Diretiva (UE) 2019/882 que enumera os requisitos de acessibilidade aplicáveis aos produtos e serviços abrangidos. Inclui requisitos funcionais de desempenho e requisitos específicos por categoria. Reproduzido na ordem jurídica portuguesa pelo Decreto-Lei n.º 82/2022.
Anexo IV (Diretiva 2019/882) — Ficheiro Técnico: Anexo da Diretiva (UE) 2019/882 que define o conteúdo da documentação técnica que o operador económico tem de elaborar para demonstrar a conformidade do produto com os requisitos de acessibilidade. O ficheiro técnico tem de ser conservado durante cinco anos após a colocação do produto no mercado (artigo 20.º).
Anexo V (Diretiva 2019/882) — Declaração UE de Conformidade: Modelo da Declaração UE de Conformidade que o fabricante elabora e assina, declarando, sob a sua exclusiva responsabilidade, que o produto cumpre os requisitos de acessibilidade aplicáveis. A declaração tem de ser traduzida para a língua oficial do Estado-Membro em que o produto é colocado no mercado.
Anexo VI (Diretiva 2019/882) — Critérios de Encargo Desproporcionado: Anexo da Diretiva (UE) 2019/882 que estabelece os critérios para avaliar se o cumprimento dos requisitos de acessibilidade implica encargos desproporcionados para o operador económico (rácio custo/benefício, dimensão da empresa, custo estimado vs. benefício para as pessoas com deficiência). A invocação tem de ser documentada e reavaliada no mínimo de cinco em cinco anos.
Annex I: An annex to EAA Directive 2019/882 that lists the accessibility requirements for products and services covered by the Act, including functional performance criteria.
Annex II: An annex to EAA Directive 2019/882 that lists the products and services subject to the Act's accessibility requirements.
Annex III: An annex to EAA Directive 2019/882 that sets out examples of accessibility solutions for selected product and service categories.
Annex IV: An annex to EAA Directive 2019/882 specifying the information to be included in the technical documentation submitted for conformity assessment.
Annex V: An annex to EAA Directive 2019/882 providing the template for the EU Declaration of Conformity.
Annex VI: An annex to EAA Directive 2019/882 setting out the criteria that define microenterprises exempt from some obligations under the Act.
APCA: Accessible Perceptual Contrast Algorithm. A modern method for calculating color contrast based on human perception, proposed for WCAG 3.0 as a replacement for the current contrast ratio formula.
APG: ARIA Authoring Practices Guide. A W3C resource that provides guidance on how to build accessible web components using WAI-ARIA, including design patterns for common widgets.
ARIA: Accessible Rich Internet Applications. A set of attributes that define ways to make web content and web applications more accessible by providing semantic information to assistive technologies.
ARIA Properties: ARIA attributes that define characteristics of a UI element that are less likely to change over time than states, such as aria-label, aria-describedby, and aria-required.
ARIA Roles: ARIA attributes that define the type or purpose of a UI element (e.g. role="button", role="dialog"), enabling assistive technologies to understand and convey the element's function to users.
ARIA States: ARIA attributes that express the current condition of a UI element, such as aria-checked, aria-expanded, or aria-disabled. States are dynamic and change in response to user interactions.
ASAE: Autoridade de Segurança Alimentar e Económica. Entidade portuguesa que atua como autoridade de fiscalização do mercado relativamente a produtos abrangidos pelo Decreto-Lei n.º 82/2022, em articulação com o INR, I. P. e com as restantes autoridades competentes.
Assertive (ARIA): A live region politeness setting (aria-live="assertive") that causes screen readers to interrupt current speech to announce updates immediately. Used for critical alerts; use sparingly to avoid disrupting users.
Assistive Technology: Hardware or software that helps people with disabilities use technology, such as screen readers, magnification software, voice control software, and refreshable Braille displays. Defined in EN 301 549.
ATAG: Authoring Tool Accessibility Guidelines. A W3C standard that defines how authoring tools (e.g. CMS platforms, code editors) should make the authoring interface accessible and help authors produce accessible content.
Ato Europeu da Acessibilidade (EAA): Designação corrente da Diretiva (UE) 2019/882 do Parlamento Europeu e do Conselho, de 17 de abril de 2019, relativa aos requisitos de acessibilidade dos produtos e serviços. Em Portugal, foi transposta pelo Decreto-Lei n.º 82/2022, de 6 de dezembro, com aplicação aos produtos e serviços colocados no mercado a partir de 28 de junho de 2025.
Audio Description: Narration added to a video's audio track that describes visual information not conveyed by the existing dialogue or sound, enabling blind users to follow video content. Required by WCAG 2.2 SC 1.2.3 and 1.2.5.
Authoring Tool: Software used to create or edit web or non-web content, such as a CMS, HTML editor, or document processor. Authoring tools have their own accessibility standard: ATAG. Also defined in EN 301 549.
Avaliação da Conformidade: Procedimento pelo qual se demonstra que um produto ou serviço cumpre os requisitos de acessibilidade da Diretiva (UE) 2019/882. Para produtos, segue o módulo previsto no artigo 15.º (controlo interno da produção, Anexo III). Para serviços, é efetuada nos termos do artigo 13.º.

B

Banco de Portugal: Banco central da República Portuguesa. No âmbito da acessibilidade dos serviços bancários ao consumidor, atua em articulação com o INR, I. P. para a fiscalização do cumprimento dos requisitos do Decreto-Lei n.º 82/2022 aplicáveis às instituições de crédito e às sociedades financeiras.
BITV: Barrierefreie-Informationstechnik-Verordnung. Germany's national regulation implementing web accessibility requirements, based on WCAG and EN 301 549.

C

Captions: Synchronized text transcriptions of the audio content in a video, including speech and relevant non-speech sounds. Required for pre-recorded media by WCAG 2.2 SC 1.2.2 and for live media by SC 1.2.4.
CE Marking: A conformity marking indicating that a product meets EU safety, health, and other requirements including, where applicable, the accessibility requirements of EAA Directive 2019/882.
Closed Captions: Captions that can be toggled on or off by the viewer, typically embedded as a separate data track in the video file rather than burned into the image. Contrasted with open captions.
Closed Functionality: A characteristic of ICT where users cannot attach, install, or use assistive technology. Closed-functionality systems must meet accessibility requirements by other means. Defined in EN 301 549.
CMVM: Comissão do Mercado de Valores Mobiliários. Entidade reguladora do mercado de capitais em Portugal. Pode atuar como autoridade competente para a fiscalização da acessibilidade dos serviços financeiros prestados a consumidores que estejam abrangidos pelo Decreto-Lei n.º 82/2022.
CNPD: Comissão Nacional de Proteção de Dados. Autoridade pública independente portuguesa responsável pela aplicação do Regulamento Geral sobre a Proteção de Dados (RGPD) e pela articulação entre proteção de dados e acessibilidade no contexto dos serviços digitais.
Coima: Sanção pecuniária administrativa aplicável em caso de incumprimento. As coimas pelo incumprimento do Decreto-Lei n.º 82/2022 são fixadas no diploma e variam consoante a gravidade da infração e a dimensão do operador económico, podendo ser agravadas em caso de reincidência.
Color Contrast: The difference in luminance or colour between two visual elements, typically foreground text and its background. WCAG 2.2 SC 1.4.3 requires a minimum contrast ratio of 4.5:1 for normal text.
Conformance Level: One of three tiers (A, AA, AAA) that indicate the degree of WCAG compliance. Level A is the minimum; Level AA is typically required by law; Level AAA represents the highest standard.
Conformidade Aparente: Estado em que um produto ou serviço cumpre uma norma harmonizada cuja referência foi publicada no Jornal Oficial da União Europeia. Os produtos ou serviços que cumpram a EN 301 549 (2021-03) beneficiam de presunção de conformidade com os requisitos do Decreto-Lei n.º 82/2022.
Conformity Assessment: The process of demonstrating that a product or service meets the accessibility requirements of EAA Directive 2019/882 or a harmonised standard. Per EAA Article 12.
Consistent Navigation: The requirement that navigation mechanisms appearing on multiple pages within a website occur in the same relative order each time. Defined in WCAG 2.2 SC 3.2.3.
Content: Information and sensory experience communicated to the user through software, including code or markup that defines the structure, presentation, and interactions of a web page or application. Defined in EN 301 549.
Content on Hover: Additional content that appears when a user hovers over or focuses a trigger. WCAG 2.2 SC 1.4.13 requires such content to be dismissible, hoverable, and persistent to support keyboard and pointer users.
Corrective Measures: Actions that an economic operator must take when a product or service is found to be non-compliant with EAA requirements, as directed by a market surveillance authority. Per EAA Article 18.
CPABE: Certified Professional in Accessibility Business Environment. An IAAP certification for professionals who focus on the business and management aspects of digital accessibility programmes.
CPACC: Certified Professional in Accessibility Core Competencies. The foundational IAAP certification covering accessibility principles, disability types, assistive technologies, and relevant standards.
Critérios de Sucesso WCAG: Os 87 critérios testáveis das Diretrizes para a Acessibilidade do Conteúdo Web 2.2 (WCAG 2.2), organizados nos princípios Percetível, Operável, Compreensível e Robusto. A norma harmonizada EN 301 549 referencia o nível AA da WCAG 2.1 para conteúdos Web.
CSS Media Queries: CSS rules that apply styles conditionally based on device characteristics such as screen size, resolution, or user preferences (e.g. prefers-reduced-motion, prefers-color-scheme). Essential for responsive and accessible design.
Cure Period: A defined window of time given to an economic operator to remedy a non-conformity before further enforcement action is taken. Referenced in the enforcement provisions of national EAA transpositions.

D

Declaração de Acessibilidade: Documento publicado pelo operador económico ou pela entidade pública que declara o nível de cumprimento dos requisitos de acessibilidade de um sítio Web, aplicação móvel, produto ou serviço, identifica os conteúdos não acessíveis, indica alternativas e disponibiliza um mecanismo de comunicação. Obrigatória nos termos do Decreto-Lei n.º 82/2022 (setor privado) e do Decreto-Lei n.º 83/2018 (setor público).
Declaração UE de Conformidade: Documento elaborado e assinado pelo fabricante, em que este declara, sob a sua exclusiva responsabilidade, que o produto cumpre os requisitos de acessibilidade aplicáveis. O modelo consta do Anexo V da Diretiva (UE) 2019/882.
Declaration of Conformity: A formal document in which an economic operator declares that a product or service meets all applicable accessibility requirements of EAA Directive 2019/882. The template is provided in Annex V.
Decreto-Lei n.º 82/2022: Decreto-Lei n.º 82/2022, de 6 de dezembro. Diploma que transpõe para a ordem jurídica portuguesa a Diretiva (UE) 2019/882, estabelecendo os requisitos de acessibilidade aplicáveis a determinados produtos e serviços. Publicado no Diário da República n.º 234/2022, Série I.
Decreto-Lei n.º 83/2018: Decreto-Lei n.º 83/2018, de 19 de outubro. Diploma que transpõe a Diretiva (UE) 2016/2102, relativa à acessibilidade dos sítios Web e das aplicações móveis dos organismos do setor público. Aplica-se à administração pública central, regional e local e a outros organismos abrangidos.
DGCI: No contexto da acessibilidade, sigla utilizada para referir orientações da Direção-Geral de Comércio Interno em matéria de proteção do consumidor. Articula-se com a ASAE e com o INR, I. P. na fiscalização dos requisitos de acessibilidade aplicáveis ao retalho eletrónico.
Diário da República: Jornal oficial da República Portuguesa, no qual são publicados os atos legislativos e regulamentares, incluindo o Decreto-Lei n.º 82/2022 (publicado no DR n.º 234/2022, Série I, de 6 de dezembro). Disponível em diariodarepublica.pt.
Directive 2019/882: The official legislative reference for the European Accessibility Act, adopted on 17 April 2019, requiring EU member states to transpose its requirements into national law by 28 June 2022, with obligations applying from 28 June 2025.
Distribuidor: Pessoa singular ou coletiva da cadeia de abastecimento, distinta do fabricante e do importador, que disponibiliza um produto no mercado da União. O distribuidor é obrigado a verificar a marcação CE, a Declaração UE de Conformidade e as instruções de utilização antes de disponibilizar o produto (artigo 9.º do Decreto-Lei n.º 82/2022).
Distributor: Any person in the supply chain who makes a product available on the EU market but is not the manufacturer or importer. Distributors have obligations under EAA Directive 2019/882 to ensure products they supply are compliant.
DOM: Document Object Model. A programming interface that represents an HTML or XML document as a tree of objects, which scripts and assistive technologies use to interact with web content.

E

Economic Operator: Any party in the supply or provision chain of a product or service covered by EAA Directive 2019/882, including manufacturers, importers, distributors, and service providers.
EN 301 549 (2021-03): Norma europeia harmonizada publicada pelo ETSI/CEN/CENELEC que estabelece os requisitos de acessibilidade aplicáveis a produtos e serviços de TIC. A versão de março de 2021 (V3.2.1) é a referência para a Diretiva (UE) 2019/882 e incorpora a WCAG 2.1 Nível AA para conteúdo Web.
Encargo Desproporcionado: Fundamento previsto no artigo 14.º da Diretiva (UE) 2019/882 que permite ao operador económico não cumprir um requisito de acessibilidade quando o cumprimento implicar uma alteração significativa da natureza do produto ou serviço ou um encargo desproporcionado. A invocação tem de ser documentada de acordo com os critérios do Anexo VI.
Enforcement Authority: A national body designated by each EU member state to monitor and enforce compliance with the EAA. Per EAA Article 21, member states must designate at least one market surveillance authority.
Error Identification: The requirement to identify and describe input errors in text when a user submits information that is not accepted. Defined in WCAG 2.2 SC 3.3.1.
ETSI: European Telecommunications Standards Institute. A standards body that publishes EN 301 549, the harmonised ICT accessibility standard referenced by the EAA.
European Accessibility Act: EU Directive 2019/882 requiring that a wide range of products and services placed on the EU market after 28 June 2025 meet defined accessibility requirements. The EAA harmonises accessibility rules across all member states.
Eye Tracking: An input technology that allows users to control a computer by moving their eyes, used by people with severe motor impairments. Accessible interfaces must work with eye-tracking systems as a pointer input.

F

Fabricante: Pessoa singular ou coletiva que fabrica um produto ou que manda projetar ou fabricar um produto e o coloca no mercado em seu próprio nome ou marca. O fabricante é o principal responsável pela conformidade do produto com os requisitos de acessibilidade (artigo 7.º do Decreto-Lei n.º 82/2022).
Failure: A specific implementation that is known to cause a WCAG success criterion not to be satisfied. Failures are documented by the W3C as definitive examples of non-conformance.
Fiscalização do Mercado: Atividades das autoridades nacionais destinadas a verificar se os produtos e serviços disponibilizados no mercado cumprem os requisitos aplicáveis. Em Portugal, a fiscalização da acessibilidade é coordenada pelo INR, I. P. em articulação com a ASAE, a ANACOM, o Banco de Portugal e a CMVM (artigo 21.º do Decreto-Lei n.º 82/2022).
Focus Indicator: A visible highlight or outline that shows which interactive element currently has keyboard focus. WCAG 2.2 SC 2.4.7 requires a visible focus indicator; SC 2.4.11 adds minimum size and contrast requirements.
Focus Management: The practice of programmatically controlling keyboard focus, especially in dynamic content such as modals, single-page apps, and custom widgets, to ensure users do not lose their position.
Focus Order: The sequence in which interactive elements receive keyboard focus when the user presses Tab. WCAG 2.2 SC 2.4.3 requires the focus order to preserve meaning and operability.
Focus Trap: A pattern where keyboard focus is intentionally restricted to a specific region of the interface, most commonly a modal dialog, so users cannot navigate outside it while the dialog is open.
Forced Colors: A browser/OS mode that overrides an author's colours with a high-contrast palette chosen by the user. The CSS forced-colors media feature lets authors adapt layouts for this mode without removing contrast enhancements.
Functional Performance Criteria: A set of overarching accessibility requirements in EN 301 549 (Clause 4) and EAA Annex I that ensure ICT is usable by people with a range of disabilities when specific technical requirements cannot be applied.
Fundamental Alteration: A change to a product or service that would fundamentally change its basic nature. Under EAA Article 14, operators are not required to make changes that would constitute a fundamental alteration.

G

GDPR: General Data Protection Regulation. An EU regulation on data protection and privacy in the European Union and the European Economic Area.
Graceful Degradation: A design strategy where a website or application is built with full functionality first and then adapted to work in less-capable environments, including older browsers and assistive technologies.

H

Hardware: Physical electronic components of ICT, such as terminals, kiosks, and ATMs. Hardware products are subject to accessibility requirements under EN 301 549 and EAA Directive 2019/882.
Harmonised Standard: A European standard whose reference has been published in the Official Journal of the EU. Products or services meeting a harmonised standard benefit from a presumption of conformity with the EAA requirements it covers.
Heading Level: The hierarchical rank of a heading element (h1–h6 in HTML), used to define the structure and outline of a page. WCAG 2.2 SC 1.3.1 requires headings to be marked up programmatically; SC 2.4.6 requires them to be descriptive.
High Contrast Mode: An operating system or browser setting that replaces the colour scheme with a high-contrast palette to improve readability for users with low vision. Web content should remain usable when high contrast mode is active.

I

IAAP: International Association of Accessibility Professionals. A global membership organisation that sets professional standards, offers certifications (CPACC, WAS, CPABE), and promotes the accessibility profession.
ICT: Information and Communications Technology. The broad category of technology including hardware, software, and services that process and communicate information. Defined in EN 301 549 and subject to EAA requirements.
Importador: Pessoa singular ou coletiva estabelecida na União que coloca no mercado da União um produto proveniente de um país terceiro. O importador é obrigado a verificar que o fabricante elaborou a documentação técnica e que o produto ostenta a marcação CE (artigo 8.º do Decreto-Lei n.º 82/2022).
Importer: Any natural or legal person established in the EU who places a product from a third country on the EU market. Importers have specific obligations under EAA Directive 2019/882 to verify product conformity.
Input Purpose: The intended meaning of a user input field, such as name, email, or telephone number. WCAG 2.2 SC 1.3.5 requires that the purpose of each input field be programmatically determinable to support autofill.
INR, I. P. (Instituto Nacional para a Reabilitação): Instituto Nacional para a Reabilitação, I. P. Autoridade nacional designada para coordenar a aplicação do Decreto-Lei n.º 82/2022 em Portugal. Atua como autoridade de coordenação em articulação com as autoridades sectoriais competentes (ASAE, ANACOM, Banco de Portugal, CMVM).
ISO: International Organization for Standardization. A global body that publishes international standards including accessibility-related standards such as ISO 9241-171 on software accessibility.

J

JAWS: Job Access With Speech. A widely used commercial screen reader for Windows developed by Freedom Scientific. It is a primary testing tool for web and software accessibility.

K

Keyboard Trap: A situation where keyboard focus becomes stuck inside a component and users cannot navigate away using only the keyboard. Prohibited by WCAG 2.2 SC 2.1.2 unless focus restriction is needed (e.g. a modal dialog).

L

Landmark Region: A semantically defined section of a web page (such as header, nav, main, or footer) that helps screen reader users quickly navigate to major content areas. Implemented via HTML5 sectioning elements or ARIA landmark roles.
Language of Page: The requirement that the default human language of each web page is programmatically determinable, enabling screen readers to use the correct pronunciation and rules. Defined in WCAG 2.2 SC 3.1.1.
Lei n.º 36/2011: Lei n.º 36/2011, de 21 de junho, que estabelece a adoção de normas abertas nos sistemas informáticos do Estado. Tem implicações na acessibilidade dos serviços públicos digitais e articula-se com o Decreto-Lei n.º 83/2018.
Live Region: An area of a web page where content updates dynamically without a page refresh. ARIA live regions (aria-live) notify screen reader users of changes. WCAG 2.2 SC 4.1.3 addresses status messages in live regions.
Live Region (ARIA): An ARIA pattern using the aria-live attribute to announce dynamic content updates to screen reader users. Supported politeness settings are 'polite' and 'assertive'; 'off' suppresses announcements.
Luminance: The intensity of light emitted or reflected from a surface. In WCAG colour contrast calculations, relative luminance (a linear measure based on sRGB values) is used to compute the contrast ratio between two colours.

M

Magnification Software: Assistive technology that enlarges part or all of the screen for users with low vision, such as Windows Magnifier or ZoomText. Web content should remain usable at high zoom levels per WCAG 2.2 SC 1.4.4.
Manufacturer: Any natural or legal person who manufactures a product or has a product designed or manufactured and markets it under their own name. Manufacturers have primary obligations under EAA Directive 2019/882.
Marcação CE: Marcação por meio da qual o fabricante declara que o produto está em conformidade com os requisitos aplicáveis estabelecidos na legislação de harmonização da União. Aposta-se nos produtos abrangidos pela Diretiva (UE) 2019/882 antes da colocação no mercado (artigo 17.º).
Market Surveillance: Activities and measures taken by national authorities to ensure that products and services on the EU market comply with applicable requirements, including EAA accessibility obligations. Per EAA Chapter VII.
Microempresa: Empresa que emprega menos de 10 pessoas e cujo volume de negócios anual ou balanço total anual não excede 2 milhões de euros. As microempresas que prestam serviços abrangidos beneficiam de uma derrogação dos requisitos de acessibilidade (artigo 4.º, n.º 5 da Diretiva (UE) 2019/882; Anexo VI).
Microenterprise: An enterprise with fewer than 10 employees and annual turnover or balance sheet total not exceeding €2 million. Microenterprises providing services are exempt from EAA accessibility requirements per Article 14 and Annex VI.
Motion Actuation: Functionality triggered by device motion or user gestures (e.g. shaking a phone). WCAG 2.2 SC 2.5.4 requires that such functionality can also be operated by conventional interface controls and the motion response can be disabled.

N

Name Role Value: A WCAG requirement (SC 4.1.2) that all user interface components have a programmatically determinable name and role, and that states, properties, and values that can be set by the user are exposed to assistive technologies.
National Transposition: The process by which each EU member state enacts domestic legislation to give effect to an EU directive. Member states were required to transpose EAA Directive 2019/882 into national law by 28 June 2022.
Non-text Content: Any content that is not text, including images, charts, audio, and video. WCAG 2.2 SC 1.1.1 requires a text alternative for all non-text content.
Non-web Document: A document that is not a web page but is made available or intended to be made available via the web, such as a PDF or Word document. Subject to accessibility requirements in EN 301 549 Chapter 10.
Norma Harmonizada: Norma europeia adotada com base num pedido da Comissão e cuja referência foi publicada no Jornal Oficial da União Europeia. Os produtos ou serviços que cumpram uma norma harmonizada beneficiam de presunção de conformidade. A norma harmonizada para a Diretiva (UE) 2019/882 é a EN 301 549 (2021-03).
Notified Body: A third-party organisation designated by an EU member state to assess the conformity of certain products with EU regulatory requirements. Relevant where mandatory third-party conformity assessment is required under the EAA.
NVDA: NonVisual Desktop Access. A free, open-source screen reader for Windows developed by NV Access. It is widely used for accessibility testing alongside JAWS and VoiceOver.

O

Open Captions: Captions that are permanently visible and burned into the video image and cannot be turned off by the viewer. Contrasted with closed captions, which are a separate selectable track.
Operable: The second of the four WCAG principles. User interface components and navigation must be operable — all functionality must be available from a keyboard, and users must have enough time and control.
Operable Part: A part of hardware ICT that requires physical interaction to operate, such as a button, coin slot, or card reader. EN 301 549 sets accessibility requirements for operable parts, including reachability and force requirements.
Operador Económico: Designação genérica que abrange o fabricante, o mandatário, o importador, o distribuidor e o prestador de serviços, conforme aplicável. Cada categoria tem obrigações específicas previstas nos artigos 7.º a 13.º do Decreto-Lei n.º 82/2022.

P

Parsing: The ability of browsers and assistive technologies to correctly interpret the markup of a web page. WCAG 2.2 SC 4.1.1 (historically important, now obsolete in WCAG 2.2) required valid, well-formed HTML to avoid parsing errors.
Perceivable: The first of the four WCAG principles. Information and user interface components must be presentable to users in ways they can perceive — content must be available to at least one sense.
Platform Software: Software that provides a platform on which other software can run, such as an operating system or a browser. Platform software must expose accessibility APIs that assistive technologies can use. Defined in EN 301 549.
Pointer Cancellation: A WCAG requirement (SC 2.5.2) that functions activated by a single pointer can be cancelled or undone to prevent accidental activation, for example by requiring the up-event rather than the down-event.
Polite (ARIA): A live region politeness setting (aria-live="polite") that causes screen readers to announce updates when the user is idle, without interrupting current speech. Suitable for non-critical notifications.
Portable ICT: ICT designed to be moved and used in different locations, such as a laptop, tablet, or mobile phone. Accessibility requirements for portable ICT are defined in EN 301 549 and the EAA.
POUR: An acronym for the four principles of WCAG: Perceivable, Operable, Understandable, and Robust. All WCAG success criteria fall under one of these four principles.
Prefers Color Scheme: A CSS media feature that detects whether the user has requested a light or dark colour scheme from their operating system. Respecting this preference supports users with photosensitivity and low vision.
Prefers Reduced Motion: A CSS media feature that detects whether the user has requested that animations and transitions be reduced or eliminated. WCAG 2.2 SC 2.3.3 (AAA) and good practice require respecting this setting.
Prestador de Serviços: Pessoa singular ou coletiva que fornece um serviço no mercado da União ou que se propõe fornecer tal serviço a consumidores na União. O prestador de serviços é responsável por garantir que o serviço cumpre os requisitos de acessibilidade (artigo 13.º do Decreto-Lei n.º 82/2022).
Presumption of Conformity: A legal benefit whereby compliance with a harmonised standard is taken as sufficient proof that the applicable regulatory requirements (e.g. EAA accessibility requirements) are met, without further proof being needed.
Programmatically Determined: Information that can be reliably extracted by user agents, including assistive technologies, from the code of a web page or application. Multiple WCAG success criteria require information to be programmatically determinable.
Progressive Enhancement: A design strategy that builds core accessible functionality first using semantic HTML, then adds styling and scripted enhancements in layers, ensuring the content works for all users regardless of their browser or assistive technology.

R

Reading Order: The sequence in which content is read by assistive technologies, determined by the order of elements in the DOM. WCAG 2.2 SC 1.3.2 requires the reading order to be meaningful.
Real-time Text: A communication method where text is transmitted character by character as it is typed, enabling people who are deaf, hard of hearing, or have speech disabilities to communicate in real time. Defined in EN 301 549.
Reflow: The ability of content to reformat into a single column without horizontal scrolling when the viewport is narrowed or text is enlarged. Required by WCAG 2.2 SC 1.4.10 to support users who need large text.
Refreshable Braille Display: A hardware device that converts text to Braille by raising and lowering small pins, enabling blind users or deaf-blind users to read content. Screen readers typically support output to Braille displays.
Relative Luminance: A measure of the brightness of a colour on a scale from 0 (absolute black) to 1 (absolute white), computed from sRGB colour values using the formula defined in WCAG 2.x and used to calculate the contrast ratio.
Relay Service: A telecommunications service that enables communication between people with and without hearing or speech disabilities, for example through text relay or video relay. Covered by EN 301 549 and EAA requirements.
Resolução do Conselho de Ministros n.º 155/2007: Resolução que aprova o Plano de Ação para a Sociedade da Informação e que, entre outros aspetos, estabelece orientações para a acessibilidade dos sítios Web da Administração Pública. Antecede e complementa o Decreto-Lei n.º 83/2018.
Responsive Design: A web design approach that adapts layout and content to the user's viewport size and device capabilities. Responsive design supports accessibility by enabling reflow (WCAG 2.2 SC 1.4.10) and appropriate touch targets.
RGAA: Référentiel Général d'Amélioration de l'Accessibilité. France's national accessibility framework, based on WCAG 2.1, used to assess and certify accessibility for public sector digital services.
Robust: The fourth WCAG principle. Content must be robust enough to be reliably interpreted by a wide variety of user agents, including current and future assistive technologies.
Roving Tabindex: A keyboard management pattern for composite widgets (e.g. tab panels, toolbars) where only one item in the group is in the tab sequence at a time (tabindex=0) and others are removed (tabindex=-1), with arrow keys moving focus within the group.

S

SC: Success Criterion. A specific, testable accessibility requirement defined within the WCAG framework.
SCA: Strong Customer Authentication. A requirement of PSD2/PSD3 for payment security, often requiring accessible MFA solutions.
Section 508: A US law requiring federal agencies to make their electronic and information technology accessible to people with disabilities, with technical requirements aligned to WCAG 2.0 Level AA.
Semantic HTML: HTML elements used according to their intended meaning (e.g. <button> for a button, <nav> for navigation) rather than purely for visual effect. Semantic HTML provides built-in accessibility through the browser's accessibility API.
Service Provider: Any natural or legal person who provides a service covered by EAA Directive 2019/882, such as e-commerce, banking, transport, or media services. Service providers must ensure their services meet EAA accessibility requirements.
Setor Público (Acessibilidade): Conjunto de organismos da administração pública direta, indireta e autónoma, abrangidos pelo Decreto-Lei n.º 83/2018 (transposição da Diretiva (UE) 2016/2102). Os sítios Web e aplicações móveis do setor público têm de cumprir requisitos de acessibilidade próprios e publicar uma Declaração de Acessibilidade.
Skip Navigation: A link placed at the top of a web page that allows keyboard and screen reader users to bypass repeated navigation links and jump directly to the main content. Supports WCAG 2.2 SC 2.4.1.
Software User Interface: The visual and interactive elements of a software application through which users interact with it. Subject to accessibility requirements in EN 301 549 Chapter 11.
sRGB: Standard Red Green Blue. A colour space used as the reference for WCAG contrast ratio calculations. Relative luminance is computed from sRGB values using a linearisation formula defined in WCAG 2.x.
Stationary ICT: ICT intended to be used in a fixed location, such as a kiosk, ATM, or desktop computer. Accessibility requirements for stationary ICT are defined in EN 301 549 and EAA Annex I.
Status Message: A message that provides information about the status of an operation (e.g. a form submitted successfully or a shopping cart update) without receiving focus. WCAG 2.2 SC 4.1.3 requires status messages to be programmatically determinable.
Success Criterion: A specific, testable statement in WCAG that content either passes or fails. Each success criterion is assigned a conformance level (A, AA, or AAA) and has documented techniques and failures.
Sufficient Technique: A documented method that, if followed, is sufficient to meet a WCAG success criterion. The W3C publishes both sufficient and advisory techniques for each criterion.
Switch Access: An input method where users control a device using one or more switches (buttons), typically via scanning interfaces. Used by people with severe motor impairments; accessible interfaces must support single-switch and sequential scanning.

T

Tab Order: The order in which interactive elements receive keyboard focus when the user presses the Tab key, determined by the DOM order and any tabindex values. See also Focus Order.
TalkBack: The built-in screen reader for Android devices, developed by Google. It is a primary testing tool for native Android and mobile web accessibility.
Target Size: The area of an interactive element available for pointer input. WCAG 2.2 SC 2.5.8 (AA) requires a minimum target size of 24×24 CSS pixels; SC 2.5.5 (AAA) requires 44×44 CSS pixels.
Technical File: Documentation compiled by a manufacturer that demonstrates a product meets EAA requirements, including design specifications, test results, and risk assessments. Required content is specified in EAA Annex IV.
Text Alternative: Any text that serves as an equivalent for non-text content, enabling the same information to be conveyed to users who cannot access the original. The broadest category covering alt text, captions, transcripts, and descriptions.
Text Spacing: The ability to adjust letter spacing, word spacing, line height, and paragraph spacing without loss of content or functionality. WCAG 2.2 SC 1.4.12 defines specific spacing thresholds that must not cause content loss.
Touch Target: The area of a screen that responds to a touch gesture. Adequate touch target size is critical for users with motor impairments; see Target Size (WCAG 2.2 SC 2.5.8) and EN 301 549 requirements for hardware operable parts.
Transitional Period: The period between the EAA's entry into force and the date its requirements become enforceable (28 June 2025), during which economic operators are expected to prepare for compliance. Some service providers may have a further 5-year transition to 2030.
Transposition: The act of converting an EU directive into national law. EAA Directive 2019/882 required member states to complete transposition by 28 June 2022.
Two-way Voice Communication: A service or feature that allows real-time spoken communication between two or more people, such as a phone call or video call. Subject to specific accessibility requirements in EN 301 549.

U

UAAG: User Agent Accessibility Guidelines. A W3C standard that defines how web browsers and media players should make web content accessible and support assistive technologies.
Understandable: The third of the four WCAG principles. Information and the operation of the user interface must be understandable — content must be readable, pages must behave predictably, and users must be helped to avoid and correct mistakes.
User Agent: Software that retrieves and renders web content, including web browsers, media players, and assistive technologies. User agents must expose content accessibly; their own accessibility requirements are defined in UAAG.

V

Video Communication: A real-time communication service that transmits video alongside audio or text, such as video calling. EN 301 549 specifies accessibility requirements for video communication products and services.
Viewport: The visible area of a web page within the browser window. Content should be designed to work at different viewport sizes (responsive design) and at 400% zoom without loss of content (WCAG 2.2 SC 1.4.10 Reflow).
Vigilância do Mercado: Sinónimo de fiscalização do mercado. Conjunto de atividades realizadas pelas autoridades para garantir que os produtos disponibilizados cumprem os requisitos aplicáveis e para prevenir riscos para os consumidores. Quadro definido no Regulamento (UE) 2019/1020.
Voice Control: An input technology that allows users to control a device entirely by speaking, such as Apple Voice Control or Dragon NaturallySpeaking. Accessible interfaces must support voice control by ensuring interactive elements have visible, speakable labels.
VoiceOver: The built-in screen reader on Apple devices (macOS, iOS, iPadOS). It is a primary testing tool for web and native app accessibility on Apple platforms.
VPAT: Voluntary Product Accessibility Template. A standardized template used to generate an Accessibility Conformance Report (ACR).

W

W3C: World Wide Web Consortium. The international standards body that develops and maintains web standards including WCAG, ARIA, ATAG, and UAAG.
WAI: Web Accessibility Initiative. A project of the W3C that develops guidelines and resources for web accessibility, including WCAG, ATAG, UAAG, and ARIA.
WAI-ARIA: Web Accessibility Initiative – Accessible Rich Internet Applications. The full name of the ARIA specification, which defines roles, states, and properties for making dynamic web content accessible.
WAS: Web Accessibility Specialist. An IAAP certification for professionals with deep technical expertise in testing and implementing web accessibility, particularly against WCAG.
WCAG: Web Content Accessibility Guidelines. The international standard for web accessibility published by the W3C Web Accessibility Initiative (WAI), with WCAG 2.2 being the current version.
WCAG 2.2: Diretrizes para a Acessibilidade do Conteúdo Web (Web Content Accessibility Guidelines), versão 2.2, publicadas pelo W3C em outubro de 2023. Compostas por 87 critérios de sucesso organizados em quatro princípios: Percetível, Operável, Compreensível e Robusto. A EN 301 549 (2021-03) referencia o nível AA da WCAG 2.1 (a norma é atualizada para incorporar a WCAG 2.2).
Web Content: Information and sensory experience delivered via the web, including text, images, sound, video, and interactive elements. Subject to WCAG requirements and EN 301 549 Chapter 9.