Glossary

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POUR Principles(also: POUR, Four Principles of Accessibility)

The four foundational principles of the Web Content Accessibility Guidelines (WCAG): Perceivable, Operable, Understandable, and Robust. Perceivable means information must be presentable in ways users can perceive (e.g., alt text for images, captions for video). Operable means…

Page Fragmentation(also: Visual Fragmentation, Content Fragmentation)

A web accessibility problem where different types of content on a web page (news articles, advertisements, navigation menus, related links) are visually grouped using colours, spacing, images, and layout but lack structural markup that would allow non-visual users to identify…

Page Landmarks(also: ARIA Landmarks, Landmark Regions, Landmark Roles)

Named regions of a web page that identify its high-level structure — for example banner, navigation, main, complementary, search, form, contentinfo — so that assistive technology can expose them as jump targets. Landmarks are typically declared with semantic HTML elements…

Page Linearization(also: Content Linearization, DOM Linearization, Source Order)

The process by which screen readers and other assistive technologies present web page content as a sequential, one-dimensional stream of text, typically following the order of elements in the HTML source code. Since web pages are designed as two-dimensional visual layouts where…

Page Magnification(also: Page Zoom, Web Page Magnification)

An accessibility feature that enlarges the entire visual presentation of a web page, including text, images, and layout elements, to make content easier to see for people with low vision or visual fatigue. Unlike text-only size increases, page magnification scales all page…

Page Sampling(also: Page Selection Strategy, Website Sampling)

The methodology used to select which pages within a website will be evaluated during an accessibility assessment. Common strategies include evaluating only the home page, testing specific page types (login, contact, sitemap), using hierarchical depth-based selection, or the…

Page Segmentation(also: Web Page Segmentation, VIPS)

The process of dividing a web page into distinct visual or structural blocks based on layout cues such as whitespace, borders, colors, and font properties. Page segmentation algorithms like Vision Based Page Segmentation (VIPS) analyze the rendered appearance of pages to…

Page Structure Preservation(also: Layout Preservation, Structure Retention)

The principle of maintaining the original spatial layout and DOM structure of a webpage when applying accessibility enhancements, content filtering, or other modifications. Preserving page structure ensures that users' mental models of familiar websites remain intact, that…

Perceived Accessibility(also: Subjective Accessibility, Accessibility-in-Use)

Perceived accessibility refers to the subjective quality by which users experience the accessibility of a website or application, as opposed to its objective compliance with accessibility standards. Research has shown that guideline-conformant websites can still be perceived as…

Personalization Semantics(also: WAI-Adapt)

A W3C specification that defines standardized semantics enabling content to be adapted to individual user needs and preferences. Personalization Semantics allows web authors to add metadata attributes to HTML elements that describe their purpose, importance, or function in a way…

Personalized Accessibility(also: Personalized Web Accessibility, User-Tailored Accessibility)

An approach to accessibility evaluation and design that considers the specific disability profile, capabilities, and needs of individual users rather than treating accessibility as a single universal property. Personalized accessibility evaluation tools filter WCAG success…

Photophobia(also: Light Sensitivity)

A genuine physiological sensitivity to bright light, flickering light, or intense visual patterns that causes symptoms such as headaches, migraines, nausea, dizziness, and disorientation. Despite its name suggesting a psychological fear, photophobia involves real neurological…

Photosensitivity(also: Photosensitive Epilepsy, PSE)

A neurological condition in which exposure to flickering light patterns, flashing graphics, or rapid luminance changes triggers physiological responses including seizures, migraines, nausea, dizziness, and disorientation. Photosensitive epilepsy, the most dangerous form, affects…

Photosensitivity(also: Light Sensitivity, Photophobia)

An abnormal sensitivity to light that can cause discomfort, pain, or visual disturbance. Photosensitivity affects many people with visual impairments and certain neurological conditions including migraine and epilepsy. In digital accessibility, photosensitivity considerations…

Plain Language(also: Plain English, Clear Language, Simple Language)

Plain language is communication that is clear, concise, and well-organized so that the intended audience can easily find, understand, and use the information. In accessibility, plain language is essential for making content accessible to people with cognitive disabilities, low…

Plain language(also: Plain English, Easy read, Simple language)

A communication approach that uses clear, concise, and well-organised writing designed to be understood the first time it is read. Plain language avoids jargon, complex sentence structures, and ambiguous wording. It is a key accessibility practice for making information…

Platform Accessibility

The degree to which online platforms (websites, apps, social media, marketplace platforms) are usable by and inclusive of disabled people. Platform accessibility encompasses not only technical compliance with standards like WCAG but also policies, algorithms, and moderation…

Presentation Independence(also: Presentation-Independent Information)

The principle that information should be stored and served in formats that can be rendered in visual, auditory, or electronic text form without loss of meaning. Presentation-independent content has no inherent visual or auditory presentation and can be adapted to the needs of…

Print Illiteracy(also: Alipi)

A condition where a literate person is unable to meaningfully access or use written web content, not because they cannot read, but because the content is presented in a language, script, or format they do not understand. Print illiteracy distinguishes itself from traditional…

Procedural Accessibility

An aspect of web accessibility that addresses the consistency and clarity of interaction sequences and workflows within digital systems. Procedural accessibility ensures that similar services follow the same patterns of interaction — for example, all online purchasing processes…

Prosumer(also: Producer-Consumer, Prosumer Content Creator)

A person who both produces and consumes content, particularly on the web. Prosumers are not formally trained in web design or development but are responsible for creating and managing user-generated content shared online — such as blog posts, newsletters, community websites, and…

Proxy Interface(also: Accessibility Proxy, Alternative Interface)

An intermediary user interface that sits between the user and the original content, re-presenting information in a more accessible format without modifying the underlying source. In accessibility contexts, proxy interfaces are used to transform visually-encoded content (like…

22 results.