Glossary

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Accessibility Metadata(also: A11y Metadata, Accessibility Annotations)

Structured information that describes the accessibility features, hazards, or access modes of digital content. Accessibility metadata can be embedded within content (such as alt text in HTML) or stored externally in separate databases or annotation systems. External…

Accessible Documentation(also: Accessible Instructions)

Documentation - user manuals, help content, installation guides, release notes, API docs - produced in a form that can be read and acted on by people with disabilities, including blind and low-vision users, users with cognitive disabilities, and Deaf users. Accessible…

Accessible Graphics(also: Accessible Images, Non-Visual Graphics)

Visual information such as charts, diagrams, maps, and illustrations that has been made perceivable and understandable to people with visual impairments through alternative formats. These formats include tactile graphics (raised line drawings, swell paper, 3D-printed models),…

Accessible PDF(also: Tagged PDF, PDF/UA)

An accessible PDF is a Portable Document Format file that has been structured with tags, reading order, alternative text for images, and other metadata so that it can be navigated and read by assistive technologies such as screen readers. The PDF/UA (Universal Accessibility)…

Accessible Slides(also: Accessible Presentation Slides, Non-Visually Accessible Slides)

Presentation slides that have been structured and annotated to be usable by people with disabilities, particularly blind and visually impaired users who access content via screen readers. Accessible slides include proper read order for elements, alternative text for images and…

Alt Text Authoring(also: Alt Text Writing, Image Description Authoring)

The process of composing alternative text descriptions for digital images, undertaken by content authors, developers, or dedicated accessibility specialists. Research has identified several barriers to effective alt text authoring, including authors not knowing what to include,…

Alternative Text(also: Alt Text, Alt Attribute)

Text associated with an image that serves the same purpose and conveys the same essential information as the image. Alternative text is a fundamental web accessibility requirement specified in WCAG, enabling screen reader users to understand image content. Standards for writing…

Anchor Text(also: Link Text, Hyperlink Text)

The visible, clickable text within a hypertext link that is intended to describe the link's destination or purpose. Descriptive anchor text (e.g., "download the annual report") provides clear information about what the user will find when they follow the link, while vague anchor…

Anchoring Effect(also: Anchoring Bias, Cognitive Anchoring)

A cognitive bias in which people rely too heavily on an initial piece of information (the "anchor") when making subsequent decisions or judgements. In the context of digital accessibility, the anchoring effect has been documented in alt text authoring, where content authors who…

Aphasia-Friendly(also: Aphasia-Accessible, Aphasia-Friendly Design)

A set of design practices for making written, spoken, and audiovisual content more accessible to people with aphasia. Established principles (Rose, Worrall, Hickson, Hoffmann) include short sentences with one idea per line, familiar everyday vocabulary, large sans-serif fonts…

Automatic Alt Text(also: AI-generated Alt Text, Auto Alt Text, Machine-generated Alt Text)

Alternative text for images that is automatically generated by artificial intelligence systems using computer vision and natural language processing. Platforms like Microsoft PowerPoint, Facebook, and Twitter have incorporated automatic alt text features to increase image…

Automatic Image Captioning(also: AI-Generated Alt Text, Machine-Generated Description, Auto Alt Text)

The use of computer vision and machine learning algorithms to automatically generate textual descriptions of images without human intervention. Social media platforms like Facebook and Instagram deploy automatic image captioning to provide alternative text for user-uploaded…

Barcode(also: Bar Code, QR Code, 1D Barcode)

A barcode is a machine-readable visual encoding of data — linear (one-dimensional, such as UPC or EAN) or matrix (two-dimensional, such as QR or DataMatrix codes). In a digital accessibility context, barcodes are commonly used as a lightweight way to attach identifying or…

Composite Figure(also: Multi-panel Figure, Multi-element Figure)

A figure that contains multiple distinct visual elements combined into a single image, such as a series of screenshots labeled (a) through (f), a set of charts showing different data sets, or a mix of photographs and diagrams. Composite figures present a significant…

Content Filtering(also: Content Adaptation, Adaptive Content Delivery)

The process of selectively displaying or hiding portions of digital content based on user preferences, roles, device capabilities, or accessibility needs. In an accessibility context, content filtering allows users to control the level of detail they receive, reducing…

Controlled Language(also: Controlled Natural Language, CL)

An explicitly defined restriction of a natural language that specifies constraints on vocabulary, grammar, and style to improve clarity, consistency, and machine processability of text. In accessibility, controlled language rules can be applied to improve the quality of content…

Data Visualization(also: Data Viz, Information Visualization)

The graphical representation of data and information using visual elements such as charts, graphs, maps, and diagrams. While data visualization is a powerful tool for communicating patterns and insights, it presents significant accessibility barriers for people with visual…

Decorative Image(also: Decorative Graphic, Presentational Image)

An image that serves a purely aesthetic or visual design purpose and does not convey meaningful information to the user. According to WCAG guidelines, decorative images should receive empty alt text (alt="") so that screen readers skip over them rather than announcing…

Defluffing(also: Content Defluffing, Clutter Removal)

The process of removing non-essential visual elements from a web page — such as banners, advertisements, decorative images, and sidebar content — to expose the core information content more directly to assistive technology users. In the context of web accessibility transcoding,…

Document Accessibility(also: Accessible Documents, Document Remediation)

The practice of creating or converting digital documents so they can be effectively accessed by people using assistive technologies, particularly screen readers. Accessible documents require proper semantic structure (headings, lists, tables with headers), logical reading order,…

Document Engineering(also: Document Design, Document Processing)

Document engineering is the discipline concerned with the principles, tools, and processes for creating, managing, transforming, and presenting documents in ways that optimise their use across different contexts and audiences. In accessibility, document engineering encompasses…

Easy Language(also: Easy-to-Read, Leichte Sprache, Easy Read)

A simplified form of written language designed to make information accessible to people with reading difficulties, including those with intellectual disabilities, prelingual hearing impairments, learning disabilities, low literacy, or limited proficiency in the language. Easy…

Easy Read(also: Easy-to-Read, Easy Language, Plain Language for Cognitive Accessibility)

A method of presenting written information in a way that is accessible to people with intellectual disabilities, learning difficulties, or low literacy. Easy Read uses short sentences, common everyday vocabulary, active voice, and clear structure, often accompanied by images or…

Embedded Description(also: Inline Description, Integrated Description)

A technique for making presentation content accessible where the speaker verbally describes relevant visual information on slides — including text, images, graphics, and other visual aids — as part of their narration during the presentation itself. Unlike audio descriptions…

Figure Accessibility(also: Chart Accessibility, Graph Accessibility)

The practice of making visual figures, charts, graphs, and diagrams in documents and publications accessible to people who cannot see them, particularly blind and low vision users. Figure accessibility encompasses multiple approaches including descriptive alt text, data tables,…

Gist Summary(also: Gist, Page Gist, Web Page Summary)

A gist summary is a brief, automatically or manually generated overview of a document or web page that captures its central theme or focus, enabling a reader to quickly assess the content's relevance without reading the entire text. In accessibility contexts, gist summaries are…

Graph Accessibility(also: Chart Accessibility, Data Visualization Accessibility)

The practice of making charts, graphs, and other data visualisations perceivable and understandable to people with disabilities, particularly those who are blind or have low vision. Graph accessibility encompasses multiple strategies including meaningful alternative text that…

Image Accessibility(also: Visual Content Accessibility)

The practice of making images perceivable and understandable to people who cannot see them, primarily through alternative text descriptions. Image accessibility is a foundational requirement of WCAG (Success Criterion 1.1.1) and involves providing text alternatives that convey…

Information Graphics(also: Infographics, Data Graphics, Statistical Graphics)

Visual representations of data, information, or knowledge designed to present complex information quickly and clearly. Common types include bar charts, line graphs, pie charts, scatter plots, and more complex visualizations. Information graphics pose significant accessibility…

Intermedia(also: Intermedia Representation)

Intermedia refers to a framework for information representation that supports diverse, adaptable, and flexible presentation modes, allowing the same content to be accessed through multiple alternative forms suited to individual needs and capabilities. Unlike multimedia (which…

Jenga Format

Jenga format is a content transformation technique designed to enhance web page readability for non-native English readers. Developed by Chen-Hsiang Yu and Robert C. Miller at MIT, it restructures text presentation by visually grouping syntactic units within sentences, making…

Link Context(also: Anchor Context, Link Surrounding Context)

The text and information surrounding a hypertext link that helps users understand the link's purpose and destination. For sighted users, link context is often apparent from the visual layout — headings, images, and nearby text provide clues about what a link does. For screen…

Link Purpose(also: Link Purpose (In Context), WCAG 2.4.4, Link Text)

A WCAG 2.4.4 Level A success criterion requiring that the purpose of each link be determinable from the link text alone, or from the link text together with its programmatically determined context (surrounding sentence, list item, table cell, containing paragraph). Links worded…

Long Description(also: Extended Description, longdesc)

A detailed textual description of an image or other non-text content that goes beyond the brief summary provided by alt text. Long descriptions are used for complex images such as charts, diagrams, infographics, or detailed illustrations where a short alt text cannot convey all…

Media Accessibility(also: Accessible Media)

The practice of ensuring that media content — including images, videos, audio, GIFs, memes, and other multimedia formats — is perceivable and understandable by people with diverse abilities. Media accessibility encompasses providing alternative text for images, captions and…

Mind Map(also: Mind Mapping, Concept Map)

A diagram that organises information radially around a central topic, with branches and sub-branches showing related ideas, supporting details, and their connections. Mind maps were popularised in the 1970s by Tony Buzan as a general study and note-taking technique. In…

Minimum Viable Description(also: MVD)

Minimum viable description (MVD) is an emerging framework for audio description that establishes the foundational level of visual information needed to provide equal access to video content without introducing bias or cognitive overload. Rather than attempting to describe…

Multilingual Accessibility(also: Multilingual Web Accessibility)

The practice of ensuring that web content and digital services are accessible to people with disabilities across multiple languages and cultural contexts. Multilingual accessibility sits at the intersection of web accessibility and web localization, recognising that translated…

Multilingualism(also: Multilingual Accessibility, Language Diversity)

The use of or support for multiple languages within a system, platform, community, or society. In the context of digital accessibility, multilingualism refers to the design and development of websites and applications that can present content and interfaces in multiple…

Multimodal Summarization(also: Multimodal Summary, MMS)

A technique for presenting information through multiple complementary formats — typically combining pictures, simplified text, and structural diagrams — to improve comprehension of complex content. Multimodal summarization is particularly valuable for accessibility because it…

Non-Visual Reference Database(also: Non-Visual Cooking Database)

A proposed structured collection that maps common visual descriptions used in cooking and other domains to their non-visual equivalents using texture, sound, smell, time, and temperature descriptors. For example, mapping the visual instruction "cook until golden brown" to…

Open Educational Resources(also: OER)

Teaching, learning, and research materials in any medium that are freely available for use, adaptation, and redistribution. OER can include textbooks, course materials, videos, assessments, and software tools, typically released under open licenses such as Creative Commons.…

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…

Presentation Accessibility(also: Slide Accessibility, Accessible Presentations)

The practice of designing and delivering slide-based presentations so that all audience members, including those with disabilities, can access the content. Key principles include verbally describing all visual content on slides (text, images, diagrams, graphs), using nouns…

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…

SMILES(also: Simplified Molecular-Input Line-Entry System)

A text-based notation system that represents chemical molecular structures as short character strings, making them both machine-readable and human-readable. For accessibility, SMILES is significant because it provides a linear, non-visual way to represent chemical structural…

Semantic Annotation(also: Semantic Markup, Semantic Tagging)

The process of adding machine-readable metadata to web content that describes the meaning of the content rather than its visual presentation. Unlike HTML markup which primarily specifies how content should be displayed (font size, color, layout), semantic annotations describe…

Semantic Level(also: Semantic Content Level, Alt Text Semantic Level)

A framework for categorizing the depth of information conveyed in alt text descriptions of data visualizations, introduced by Lundgard and Satyanarayan. The four levels are: Level 1 (construction details such as chart type, axes, and encodings), Level 2 (statistical properties…

Shadow Page(also: Shadow Site, Text-Only Alternative)

A separate, simplified version of a web page created specifically to meet accessibility requirements, typically offering a text-only or reduced-complexity version of the original content. While shadow pages can address some accessibility barriers, they are generally considered a…

Single-Source Publishing(also: Single-Source Authoring, Multi-Channel Publishing)

An authoring and publishing methodology where content is written and maintained in one master source and then automatically transformed into multiple output formats such as HTML, PDF, Braille, or mobile-optimized views. This approach is significant for accessibility because it…