AHWD key terms

An international standard published by the W3C that defines how to make web content more accessible to people with disabilities. It is organized around four principles and layered into testable success criteria at three conformance levels.

The four foundational principles of WCAG: content must be Perceivable, Operable, Understandable, and Robust. Every success criterion maps to one of these principles, and all four must be satisfied for conformance.

A single, testable requirement in WCAG, such as text alternatives for images or keyboard operability. Each has a level (A, AA, or AAA) and is written so testers can judge whether content passes or fails.

The rating of a WCAG success criterion as A (minimum), AA (standard practice, often legally referenced), or AAA (enhanced). A page claims a level only when it satisfies all criteria at that level and below.

Programmatic text that conveys the meaning or purpose of non-text content, such as an image, icon, or chart. It is exposed to assistive technology and may be visible, hidden, or provided through adjacent text.

The specific text value supplied for an image, typically through the alt attribute. It should describe the image's purpose in context, and should be empty when the image is purely decorative.

An image that adds no information and exists only for visual styling. It should be hidden from assistive technology, usually with an empty alt attribute, so users do not hear irrelevant descriptions.

The label a user agent computes for a control or region and announces to assistive technology. It can come from visible text, labels, alt text, ARIA attributes, or other sources in a defined order.

Supplementary information about an element, beyond its name, that assistive technology may announce on request. It is often supplied through aria-describedby or a title attribute and clarifies rather than labels.

A W3C specification of attributes that add roles, states, and properties to markup so custom widgets can be understood by assistive technology. It changes semantics only and does not add behavior or keyboard support.

A semantic page area, such as navigation, main, or search, that lets screen reader users jump directly between major sections. Landmarks can come from native HTML elements or equivalent ARIA roles.

A link placed early in the tab order that jumps past repeated navigation to the main content. It helps keyboard and screen reader users avoid re-traversing menus on every page.

A page area marked so that content changes are announced automatically by assistive technology without moving focus. Politeness settings control whether updates interrupt the user or wait for a pause.

Deliberately moving and tracking keyboard focus when content changes, such as opening a dialog or submitting a form. Good practice sends focus somewhere logical and returns it when the interaction ends.

A situation where keyboard focus enters a component and cannot leave using standard keys. Users who cannot operate a mouse can become stuck, so components must allow focus to move onward.

A clear on-screen indicator showing which element currently has keyboard focus. Removing outlines without providing a replacement makes keyboard navigation unusable for sighted keyboard users.

A numeric measure of luminance difference between foreground and background colors, ranging from 1:1 to 21:1. WCAG sets minimum ratios for normal text, large text, and non-text interface components.

Using color as the only way to convey information, such as red text marking an error. Because some users cannot distinguish colors, a second cue like text, icon, or pattern must also be present.

Content that adapts to a narrow viewport without requiring two-dimensional scrolling, except for content that inherently needs it like maps or data tables. It supports zoomed and small-screen reading.

The ability to enlarge text, typically up to 200 percent, without loss of content or function. It matters for low-vision users who magnify text rather than the whole page.

Assistive software that converts on-screen content into synthesized speech or braille, letting blind and low-vision users navigate by headings, links, and controls rather than by visual layout.

Software that enlarges a portion of the screen for low-vision users, often following the cursor or focus. Because only a fragment is visible at once, layouts must stay predictable when zoomed.

An input method where a user activates one or more switches, often with a head or hand movement, to scan and select on-screen items. It requires clear focus indicators and logical item order.

Software that converts spoken words into text or commands, used by people with motor or repetitive strain limitations. Interfaces must expose visible labels so users can refer to controls by name.

The property of an interface where every function can be reached and operated using a keyboard alone. It is essential for users who cannot use a mouse and foundational for many other assistive technologies.

The sequence in which assistive technology encounters content, which should match the meaningful visual order. Mismatches between visual layout and source order confuse screen reader and keyboard users.

Any hardware or software that helps a person with a disability perform tasks, such as screen readers, magnifiers, switches, or refreshable braille displays. Accessible content is designed to work with these tools.

Designing products and environments to be usable by the widest range of people possible without adaptation. It anticipates human diversity in ability, age, and situation from the start rather than adding fixes later.

An approach that deliberately includes people with diverse abilities and backgrounds throughout design and development. It treats accessibility as a core quality and involves users with disabilities in research and testing.

The mental effort required to understand and use an interface. Clear language, consistent layouts, and reduced distractions lower cognitive load, helping users with cognitive or learning disabilities.

Writing that uses common words, short sentences, and logical structure so readers can understand it on a first pass. It benefits people with cognitive disabilities, low literacy, and anyone reading under stress.

A file such as a PDF or word-processing document with structure, reading order, headings, alternative text, and table headers defined so assistive technology can interpret it correctly.

A PDF containing structural tags that identify headings, paragraphs, lists, tables, and figures. These tags provide the semantics screen readers need, which untagged PDFs generally lack.

Synchronized text of spoken dialogue and meaningful sounds displayed with video. Captions serve deaf and hard-of-hearing viewers and also help anyone watching without sound or in noisy settings.

A text version of audio or video content, often including speaker identification and relevant sounds. It gives deaf, deafblind, and some cognitive users a non-time-based way to access the material.

Narration added to video that describes important visual information not conveyed by dialogue, such as actions or on-screen text. It serves blind and low-vision viewers who cannot see the visuals.

Running tools that scan code for detectable issues such as missing alt text or low contrast. These tools catch only a subset of problems and must be combined with manual and user testing.

Human evaluation of an interface, such as keyboard-only navigation, screen reader checks, and zoom testing. It finds issues automated tools miss, including confusing reading order and unclear labels.

Observing real users with disabilities attempt tasks on a product to find barriers that standards checks may overlook. It reveals practical difficulties and validates whether fixes actually help.

A document, typically based on the VPAT template, stating how a product meets each relevant success criterion. Buyers use it to compare products and set expectations for remediation.

A structured evaluation of a product against a chosen standard, producing findings, severity, and remediation guidance. It usually combines automated scans, manual checks, and assistive technology testing.

The process of fixing accessibility defects found in testing, such as adding labels, correcting contrast, or repairing reading order. Effective remediation includes retesting to confirm the barrier is gone.

A change to a job, service, or environment that removes a barrier for a qualified person with a disability, unless it causes undue hardship. In digital contexts it may include providing accessible formats.

When a person tells an employer or service provider about their disability, often to request accommodation. Confidentiality and respectful handling of this information are legal and ethical expectations.

A public page describing a site's accessibility status, known limitations, standards targeted, and how to report problems. It sets expectations and gives users a contact route for requesting help.

European Union legislation requiring public sector websites and mobile apps to be accessible, publish statements, and provide a feedback mechanism. It references a harmonized standard aligned with WCAG.

United States federal law requiring agencies to procure and provide accessible information and communication technology. Its technical standards incorporate WCAG and apply to covered federal ICT.

United States civil rights law prohibiting discrimination against people with disabilities in public life. Courts and regulators increasingly apply it to websites and digital services of covered entities.

W3C guidance showing expected keyboard behavior, roles, and states for common widgets like tabs and dialogs. Following it helps custom components behave the way assistive technology users expect.