Glossary

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2D Tactile Display(also: Two-Dimensional Tactile Display, Graphical Tactile Display)

A type of tactile display that presents information across a two-dimensional surface, enabling blind and low vision users to access complex graphical data such as diagrams, charts, maps, and graphical user interfaces through touch. Unlike single-line Braille displays that…

360 Video(also: 360-Degree Video, Spherical Video, Omnidirectional Video)

Video content recorded or rendered to capture a full spherical or panoramic field of view, allowing viewers to look in any direction by turning their head (in a VR headset) or by dragging the view (on a screen). Unlike traditional video where a director controls the frame, 360…

360-Degree Video(also: 360 Video, VR360, Spherical Video)

Video content recorded or rendered to cover the full 360-degree sphere around the viewer, allowing them to look in any direction during playback. When viewed in a virtual reality headset, 360-degree video provides an immersive experience where users can explore the environment…

3D Audio(also: Three-Dimensional Audio, Binaural Audio, Immersive Audio)

Audio technology that creates the perception of sound sources positioned in three-dimensional space around the listener, including above, below, and at varying distances. 3D audio uses head-related transfer functions (HRTFs), interaural time differences, and distance-based…

3D Environment Model(also: Building Information Model, Spatial Model, 3D Building Model)

A detailed three-dimensional digital representation of a physical environment, such as a building interior, that includes the geometry of walls, floors, doors, windows, and fixed objects. In accessibility and navigation research, 3D environment models serve as spatial databases…

3D Gaussian Splatting(also: 3DGS, Gaussian Splatting)

An explicit 3D scene representation, introduced by Kerbl et al. in 2023, in which a scene is modelled as a cloud of anisotropic 3D Gaussians whose positions, shapes, colours, and opacities are optimised to match input views. Unlike NeRFs, which require costly neural-network…

3D Instance Segmentation

3D instance segmentation is a computer vision technique that identifies and delineates individual objects within a three-dimensional point cloud or mesh, assigning a distinct label to each detected instance. Unlike semantic segmentation (which classifies every point by…

3D Printed Model(also: 3D Print, Additive Manufacturing Model)

A physical object created through additive manufacturing (layer-by-layer material deposition) that can serve as an accessible learning tool for blind and low vision users. 3D printing enables rapid, cost-effective production of tactile models with customizable features such as…

3D Printed Tactile Model(also: 3D tactile model, Tactile 3D model, 3D-printed accessibility model)

A physical, three-dimensional object produced by additive manufacturing (for example fused deposition modelling or stereolithography) that is designed to be explored by touch rather than sight. 3D printed tactile models are used in accessibility contexts to convey information…

3D Printing(also: Additive Manufacturing, AM)

A manufacturing process that creates three-dimensional objects by depositing material layer by layer according to a digital design. Unlike subtractive manufacturing which removes material from a solid block, 3D printing builds objects additively, enabling complex geometries and…

3D Printing Pen(also: 3D Pen)

A handheld device that extrudes a quick-cooling thermoplastic filament (commonly PLA, PCL, or ABS) through a heated nozzle, leaving raised, three-dimensional lines that solidify within seconds of being drawn. In accessibility contexts, 3D pens have become a cheap and widely…

3D Printing for Accessibility(also: Accessible 3D Printing, Additive Manufacturing for Accessibility)

The use of 3D printing technology to create custom assistive devices, tactile materials, and accessible objects for people with disabilities. Applications include tactile graphics and maps, customized grips and handles for people with motor disabilities, braille labels,…

3D Reconstruction(also: Scene Reconstruction, 3D Scene Reconstruction)

The computer vision task of recovering the 3D structure of a scene - geometry, camera positions, and sometimes object trajectories - from one or more 2D images or video frames. Techniques range from classic structure-from-motion and multi-view stereo to modern learning-based…

3D-Printed Assistive Technology(also: 3D-Printed AT)

Assistive devices manufactured using 3D printing technology, typically fused deposition modeling with thermoplastic materials like PLA. These devices can be rapidly prototyped and customized to individual needs at low cost, making them particularly valuable for people who cannot…

A* Path Planning(also: A-star algorithm, A* search)

A classic graph-search algorithm (Hart, Nilsson, and Raphael, 1968) that finds the shortest or lowest-cost path between two points by combining the cost already travelled with a heuristic estimate of the remaining distance. In assistive indoor navigation for blind travellers, A*…

AAC

Abbreviation for Augmentative and Alternative Communication. AAC encompasses all forms of communication other than oral speech that are used to express thoughts, needs, wants, and ideas. This includes both unaided systems (such as gestures, sign language, and facial expressions)…

AAC Abandonment(also: AAC Device Abandonment, AT Abandonment)

The widespread phenomenon of users discontinuing their use of augmentative and alternative communication (AAC) devices, particularly common among people with aphasia. Abandonment is driven by multiple factors including poor personalization and difficulty customizing devices to…

AAC Corpus(also: AAC Text Corpus, Augmentative Communication Corpus)

A collection of text produced by or representative of Augmentative and Alternative Communication (AAC) device users, used for training and evaluating language models and word prediction systems. AAC corpora are notoriously difficult to assemble because AAC users produce text…

AAC Device(also: AAC System, Communication Device)

A dedicated hardware device or software application designed to support augmentative and alternative communication for people who cannot rely on natural speech. AAC devices range from low-tech options (communication boards, picture cards) to high-tech systems (speech-generating…

AAC Symbol Set(also: Symbol Set, Communication Symbol Set, Pictographic Symbol Set)

A standardised collection of pictographic images used in augmentative and alternative communication (AAC) to represent words, phrases, or concepts. Each symbol in a set is mapped to specific vocabulary, allowing people who cannot use spoken language to construct messages by…

ABA Reversal Method(also: ABA Design, Reversal Design)

The ABA reversal method is a single-subject experimental design in which one participant is observed across three phases: a baseline (A), an intervention (B), and a return to baseline (A). By comparing performance across the A-B-A sequence, the design isolates the effect of the…

ABC Model(also: Antecedent-Behavior-Consequence, ABC Analysis, ABC Framework)

A behavioural-science framework, rooted in B. F. Skinner's operant conditioning, that analyses any observed behaviour as a three-part sequence: Antecedent (the situation, trigger, or context immediately before the behaviour), Behaviour (what the person actually did), and…

ABC Notation(also: ABC Text, ABC Music Notation)

A shorthand ASCII text format for representing music notation using plain characters that can be read directly by screen readers. In ABC notation, pitch is represented by letters (A-G for different octaves), rhythm by numbers and fractions, and musical elements like key…

ABET(also: Accreditation Board for Engineering and Technology)

A non-profit, non-governmental body that accredits US post-secondary programmes in applied and natural science, computing, engineering, and engineering technology. ABET’s Computing Accreditation Commission and Engineering Accreditation Commission set the programme outcomes that…

ACCMD(also: ACCessibility MetaData, IMS ACCessibility MetaData)

A metadata specification developed by the IMS Global Learning Consortium for describing the accessibility characteristics of learning resources. ACCMD provides a structured way to document whether a resource contains auditory, visual, textual, or tactile information, and to…

ACM Code of Ethics(also: ACM Code of Ethics and Professional Conduct)

A statement of professional ethics maintained by the Association for Computing Machinery (ACM) that sets out the moral and professional responsibilities of computing practitioners. Significantly revised in 2018, the Code explicitly addresses accessibility and inclusion, stating…

ACT Rules(also: Accessibility Conformance Testing Rules, ACT-R)

A set of standardized, machine-readable test rules developed by the W3C that provide specific, objective criteria for evaluating whether web content meets accessibility requirements like WCAG success criteria. ACT Rules aim to reduce inconsistency between different automated…

AChecker(also: IDI Web Accessibility Checker)

An open-source web accessibility evaluation tool that checks HTML content against accessibility standards including WCAG 2.0. AChecker identifies three types of issues: known problems (definite violations detectable by rule), likely problems (probable violations requiring human…

AD Guidelines(also: Audio Description Guidelines, AD Standards)

Established rules and best practices that govern the creation of audio descriptions for video and live performances. AD guidelines cover aspects such as what to describe (actions, characters, settings, on-screen text), language style (present tense, third person, objective),…

AD Personalization(also: Audio Description Customization, Personalized Audio Description)

The practice of tailoring audio descriptions to individual user preferences rather than providing a one-size-fits-all narration. Personalization can include varying the level of detail (concise vs. comprehensive), focus (character-driven vs. environment-driven), interpretation…

AD Timing(also: Audio Description Timing, AD Placement)

The process of determining when audio descriptions should be inserted into video content. Effective AD timing requires identifying natural pauses in dialogue and significant audio where descriptions can be placed without overlapping important sound. Automated AD timing systems…

ADA(also: Americans with Disabilities Act)

A landmark United States civil rights law enacted in 1990 that prohibits discrimination against individuals with disabilities in all areas of public life, including employment, education, transportation, and access to public and private places open to the general public. The ADA…

ADA Compliance(also: Americans with Disabilities Act Compliance)

Adherence to the requirements of the Americans with Disabilities Act (ADA), a 1990 US civil rights law that prohibits discrimination against people with disabilities in public accommodations, employment, transportation, telecommunications, and government services. ADA compliance…

ADA Title II(also: Title II of the Americans with Disabilities Act)

The section of the Americans with Disabilities Act (ADA) that prohibits discrimination based on disability by public entities, including all state and local governments and their departments, agencies, and instrumentalities. Title II requires that people with disabilities have…

ADA Transition Plan(also: ADA Self-Evaluation and Transition Plan, Accessibility Transition Plan)

A document required under Title II of the Americans with Disabilities Act (ADA) that outlines how a public entity will make its programs, services, activities, and facilities accessible to people with disabilities. The plan must include an inventory of accessibility barriers, a…

ADHD(also: Attention Deficit Hyperactivity Disorder, Attention Deficit Disorder, ADD)

A neurodevelopmental condition characterized by persistent patterns of inattention, hyperactivity, and impulsivity that affect executive function, including working memory, task initiation, sustained attention, and self-regulation. ADHD affects an estimated 3-6% of adults…

ADHD(also: Attention Deficit Hyperactivity Disorder, ADD, Attention Deficit Disorder)

A neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning and development. ADHD affects working memory, executive function, and the ability to sustain attention on tasks. For digital…

ADHD Rating Scale(also: ADHD-RS, ADHD-RS-IV)

A standardised assessment tool based on DSM diagnostic criteria for evaluating the frequency and severity of ADHD symptoms in children and adolescents. Completed by parents or teachers, it measures inattentive and hyperactive-impulsive symptom clusters. In digital health and…

ADHD Subtype(also: ADHD Presentation, ADHD Type)

A classification of ADHD based on the predominant symptom pattern experienced by an individual. The three recognized subtypes are: predominantly inattentive (difficulty sustaining attention, following through on tasks, and organizing activities), predominantly…

ADHD Tax(also: Disability Tax, Crip Tax)

The additional financial, emotional, and intellectual costs that people with ADHD and other neurodivergent conditions must pay to navigate systems designed for neurotypical functioning. Examples include purchasing productivity apps, planners, and wearable devices to compensate…

ADKAR(also: ADKAR Model, ADKAR Change Management Model)

A goal-oriented change management model developed by Prosci that identifies five sequential outcomes an individual must achieve for organizational change to succeed: Awareness of the need for change, Desire to support and participate in it, Knowledge of how to change, Ability to…

AHEAD(also: Association on Higher Education And Disability)

The Association on Higher Education And Disability, a professional organization that provides resources, guidelines, and program standards for disability services offices in postsecondary education. AHEAD develops standards that outline minimum essential services disability…

AI Accountability(also: Algorithmic Accountability, AI Governance)

The principle that developers, deployers, and operators of AI systems should be held responsible for the outcomes those systems produce, including negative effects on marginalized populations such as people with disabilities. AI accountability encompasses transparency about how…

AI Auditing(also: Algorithmic Auditing, AI Audit)

The systematic evaluation of an AI system's outputs, behaviour, or training data to identify harms such as bias, stereotype reproduction, or accessibility failures. Audits may be conducted by industry professionals, external researchers, regulators, or end users, and are…

AI Bias(also: Algorithmic Bias, Machine Learning Bias)

Systematic and unfair discrimination in AI system outputs that arises from biased training data, flawed model design, or unrepresentative assumptions embedded in the development process. In accessibility contexts, AI bias can manifest as systems that reinforce stereotypes about…

AI Chatbot Accessibility(also: Accessible AI, LLM Accessibility)

The design and evaluation of AI-powered chatbots and large language model applications to ensure they are usable by and beneficial to people with disabilities. This encompasses both the technical accessibility of chatbot interfaces (screen reader compatibility, keyboard…

AI Code Assistant(also: AI coding assistant, AI programming assistant)

A developer tool powered by large language models that provides code completion, natural-language explanations, refactoring, bug fixes, and conversational programming support inside an IDE or editor. Modern AI code assistants (e.g., GitHub Copilot, Cursor, Cline) often include…

AI Code Generation(also: Code Generation Model, AI Coding Assistant, LLM Code Generation)

The use of large language models and machine learning to automatically generate, suggest, or complete source code based on natural language prompts or existing code context. Tools like GitHub Copilot, ChatGPT, and Amazon CodeWhisperer are integrated into developer workflows as…

AI Coding Assistant(also: AI Pair Programmer, Code Copilot)

An artificial intelligence tool integrated into code editors that assists developers by generating code suggestions, completing code snippets, and answering programming questions using large language models trained on code repositories. In accessibility contexts, AI coding…

AI Companion(also: Chatbot Companion, AI Companionship)

An AI companion is an artificial-intelligence system - typically a text, voice or avatar-based chatbot built on a large language model - explicitly designed to offer users a sense of social presence, intimacy or relational support, marketed as a friend, confidant, mentor or…