Glossary

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Collaborative Design(also: Collaborative Design Session)

A design approach where multiple participants work together to create shared design solutions, building on each other's ideas and negotiating design decisions collectively. In accessible design workshops with blind participants, collaborative design requires specific…

Collaborative Editing(also: Collaborative Authoring, Co-Editing)

The practice of multiple users simultaneously or sequentially creating and modifying shared documents or content. In accessibility contexts, collaborative editing poses particular challenges when participants use different modalities to interact with the same content — for…

Collaborative Ideation(also: Group brainstorming, Co-ideation)

The joint process by which a group generates, refines, clusters, and converges on ideas, typically alternating between divergent and convergent thinking. Collaborative ideation is a cornerstone of design, research, and creative practice and is commonly supported by digital…

Collaborative Learning(also: Cooperative Learning)

An educational approach involving two or more individuals working together to build knowledge or skills through interaction, information sharing, and joint problem-solving. In sign language education, collaborative learning aligns with social constructivist and sociocultural…

Collaborative Memory(also: Distributed Cognition, Shared Memory)

The process by which memory tasks and cognitive load are distributed across multiple people, typically within families or close social groups. In the context of disability and caregiving, collaborative memory refers to how family members collectively manage the memory needs of a…

Collaborative Note-Taking(also: Shared Note-Taking, Co-Note-Taking)

An educational practice where two or more people collectively take notes, annotate content, exchange feedback, and ask questions about material being learned. In the context of disability support in higher education, collaborative note-taking transforms the traditionally…

Collaborative Play(also: Cooperative Play)

Play in which two or more people work together toward a shared goal, coordinating their actions, attention, and turns rather than competing or playing in parallel. Collaborative play is a common vehicle for building social skills - imitation, joint attention, turn-taking, and…

Collaborative Robot(also: Cobot, Co-Robot)

A robot designed to work alongside humans in shared workspaces, as opposed to traditional industrial robots that operate in isolation. Cobots are of particular interest for workplace inclusion because they can reduce physical workload, adapt to individual abilities, and create…

Collaborative Tracking(also: Collaborative Self-Tracking)

Collaborative tracking is the practice of multiple people - typically a person with a health condition and their caregivers or allies - contributing to and reviewing shared health or behaviour data. It extends personal informatics from individual self-knowledge into…

Collaborative Troubleshooting(also: Cooperative Problem-Solving)

A process where two or more people work together to identify, diagnose, and resolve technical problems, sharing knowledge and strategies to reach a solution. In assistive technology contexts, collaborative troubleshooting between screen reader users presents unique challenges…

Collaborative virtual environment(also: CVE, Shared virtual space)

A computer-based distributed virtual space where multiple users can interact with one another and with virtual objects in real time from separate physical locations. For children with autism, CVEs offer controlled social practice environments that reduce the sensory overload of…

Collective Communication Access(also: CCA)

A framework developed by McDonnell et al. (2023) that reconceptualises communication access as a shared, co-constructed practice distributed across everyone involved in an interaction, rather than as an individual accommodation provided to disabled participants. CCA argues that…

Collective Quality Control(also: Community Quality Control, Crowdsourced Quality Assessment)

The process by which online communities collectively monitor, assess, and improve the quality of shared content through comments, ratings, corrections, and supplementary information. In disability communities on video platforms, collective quality control manifests as viewers…

Collective access(also: Collective communication access)

A disability justice concept that frames accessibility as a shared, relational practice created by a group rather than an individual accommodation delivered to one person. In contrast to traditional models where a disabled person requests and receives access (such as captioning…

Collision Avoidance(also: Obstacle Avoidance, Anti-Collision System)

A safety feature in assistive technology, robotics, and intelligent wheelchairs that automatically detects obstacles in the user's path and takes action to prevent impact — typically by stopping the device, alerting the user, or redirecting movement. Collision avoidance systems…

Collision Detection(also: Contact Detection, Intersection Testing)

In virtual reality and haptic systems, collision detection is the computational process of determining when virtual objects come into contact with each other or with a user's virtual representation (such as a virtual hand or cane). When a collision is detected, the system can…

Collision Prediction(also: Collision risk prediction, Trajectory prediction)

The task of estimating the future trajectories of surrounding pedestrians and obstacles and determining whether any of them will intersect with a user's own future position within a short prediction horizon (typically 2–4 seconds). In assistive technology for blind travellers,…

Color Adaptive Graphics(also: Colour Adaptive Graphics)

A technique for automatically adjusting the colours in graphical content so that objects maintain similar colour contrast relative to their reference background colours, regardless of the viewing context. Unlike recolouring approaches that focus on preserving the author's…

Color Blindness(also: Color Vision Deficiency, CVD, Colour Blindness)

A condition in which the ability to distinguish certain colors is reduced or absent, most commonly affecting the perception of red and green. Color blindness affects approximately 8% of males and 0.5% of females of Northern European descent. In music education, color-coded…

Color Contrast(also: Colour Contrast, Contrast Ratio)

The difference in luminance between foreground text (or UI components) and their background, measured as a ratio. WCAG 2.1 requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text at Level AA, and 7:1 for normal text and 4.5:1 for large text at Level…

Color Filter(also: Color Filters, Display Color Filter)

An operating-system or browser-level feature that alters how colors are rendered on screen, including grayscale, inverted colors, and filters for protanopia, deuteranopia, and tritanopia color vision deficiencies. Used by low-vision users and users with color vision deficiency…

Color Gamut(also: Colour Gamut, Gamut)

The complete range of colours that can be represented or reproduced by a particular colour space, display device, or visual system. In the context of colour vision, a trichromat's gamut encompasses the full range of colours perceivable by typical human vision, while a…

Color Histogram(also: Colour histogram, Histogram tracking)

A statistical summary of the distribution of colour values across the pixels of an image or image region, often computed in a perceptual colour space such as Lab. In assistive computer-vision systems for blind users, colour histograms are used to re-identify and track a specific…

Color Identifier(also: Color Detector, Color Recognition Device)

A color identifier is an assistive technology device or application that detects and announces the color of objects for people with vision impairments. Standalone hardware devices use a light sensor pressed against an object to identify its color and speak the result aloud.…

Color Perception(also: Color Vision, Chromatic Vision)

Color perception is the ability to detect, distinguish, and identify colors. Impairments in color perception range from complete color blindness (achromatopsia) to partial deficiencies in distinguishing specific color ranges, such as red-green or blue-yellow color vision…

Color Sonification(also: Colour Sonification, Color-Audio Encoding)

The process of translating colour information into audible sound signals, enabling people who are blind or have visual impairments to perceive colour through hearing. Color sonification systems typically map different colour properties (such as hue, saturation, and luminosity)…

Color Space(also: Colour Space, Color Model)

A mathematical model that describes the range of colours that can be represented as numerical values, typically using three or more coordinates. Common colour spaces include RGB (red, green, blue), used in digital displays; CMYK (cyan, magenta, yellow, key/black), used in…

Color Theory(also: Colour Theory)

A body of principles and guidelines for understanding how colors interact, combine, and affect perception. In accessibility contexts, color theory is important for ensuring sufficient contrast ratios, avoiding color-only information encoding, and designing for color vision…

Color Universal Design(also: CUD, Colour Universal Design)

A set of guidelines and principles developed to ensure that colour use in designs, products, and environments is accessible to people with all types of colour vision, including those with colour vision deficiency. Color Universal Design emphasizes selecting colour palettes that…

Color Vision Deficiency(also: Color Blindness, CVD, Colour Blindness)

A condition in which a person has difficulty distinguishing between certain colors, most commonly red and green (deuteranopia/protanopia), but also blue and yellow (tritanopia) or all colors (achromatopsia). Color vision deficiency affects approximately 8% of males and 0.5% of…

Colorism(also: Skin Tone Bias, Shadeism)

Colorism is a form of discrimination in which people are treated differently based on the shade of their skin tone, typically favoring lighter skin over darker skin within and across racial groups. In digital accessibility, colorism is relevant to image descriptions and AI…

Colour Commentary(also: Color Commentary, Colour commentator)

In sports broadcasting, the analytical and contextual commentary provided alongside the play-by-play — offering opinions, background on players and teams, strategy discussion, and remarks during gameplay pauses. Colour commentary conveys information that is not visually present…

Colour Contrast(also: Color Contrast, Contrast Ratio)

The measurable difference in luminance or colour between two adjacent elements, used to determine readability and visual distinguishability. WCAG defines minimum contrast ratios (4.5:1 for normal text, 3:1 for large text at AA level) based on relative luminance calculations…

Colour Palette Generation(also: Color Palette Generation, Accessible Palette Generation)

The automated or semi-automated creation of sets of colours that are distinguishable by people with different types of colour vision deficiency while meeting aesthetic and functional design requirements. Despite its importance, colour palette generation is an underrepresented…

Colour Vision Deficiency(also: CVD, Color Blindness, Colour Blindness)

A condition in which a person has difficulty distinguishing between certain colours due to differences in the cone cells of the retina. CVD affects approximately 1 in 12 men and 1 in 200 women worldwide. It is not typically a complete inability to see colour but rather a reduced…

Colour blindness(also: Color blindness, Colour vision deficiency, CVD)

A condition affecting the perception of colour, caused by absent or altered photoreceptors in the retina. The main types are classified by which colour receptors are affected: protanopia (absent red receptors), deuteranopia (absent green receptors), and tritanopia (absent blue…

Colour contrast ratio(also: Contrast ratio, Luminance contrast ratio, Color contrast)

A numerical measure of the perceived brightness difference between a foreground colour (typically text) and its background, expressed as a ratio ranging from 1:1 (no contrast, identical colours) to 21:1 (maximum contrast, black on white). WCAG defines minimum contrast ratios to…

Coloured Overlay(also: Colored Overlay, Tinted Overlay, Reading Overlay)

A transparent coloured sheet placed over text or a digital colour filter applied to a screen to reduce visual stress and improve reading comfort for some people with dyslexia, Meares-Irlen syndrome, or other visual processing difficulties. Coloured overlays work by altering the…

Colours of Confusion(also: Confusion Colors, Confusable Colours, Metameric Pairs)

Pairs or sets of colours that appear distinct to people with typical colour vision but appear identical or nearly identical to people with a specific type of colour vision deficiency. These colour pairs are predicted by CVD colour models and underlie CVD simulation tools.…

Combination Repertoire

A type of technology repertoire where multiple tools work together simultaneously to provide access for a single task. For example, a person who is deaf and hard of hearing might use automatic captions, Bluetooth hearing aids, and good lighting together during in-person…

Comic Strip Conversations(also: CSC)

A visual-support technique developed by Carol Gray (1994) for autistic children and adolescents, in which a social interaction is illustrated as a short comic strip with simple stick figures, speech bubbles, thought bubbles, and colour codes for emotion. By externalising who…

Command Recognition(also: Command Classification, Input Recognition)

The process by which a computer system interprets and classifies a user's input action — such as a gesture, voice command, or key press — as a specific intended command from a predefined vocabulary of possible commands. The accuracy of command recognition is characterised by the…

Command-Line Interface(also: CLI, Command-Driven Interface, Command Interface)

A user interface style in which the user types textual commands, usually following a defined syntax, to drive a system. Command-line interfaces are typically fast and powerful for expert users, scriptable, and efficient for repetitive work, but require users to memorise commands…

Common Ground(also: Shared Understanding, Mutual Knowledge)

The mutual knowledge, beliefs, and assumptions shared between people communicating or collaborating. In accessibility and inclusive design, establishing common ground is essential for effective collaboration between people with different sensory abilities. Sighted people often…

Common Ground(also: Grounding, Mutual Understanding)

The shared knowledge, beliefs, and assumptions that conversation participants use to understand each other. In communication theory, grounding is the process by which speakers establish and maintain this mutual understanding through strategies such as referencing shared context,…

Communicability

A quality property of interactive systems proposed by Semiotic Engineering theory, referring to the system's ability to effectively and efficiently convey to users the designer's communicative intentions, logic, and underlying interaction principles. High communicability means…

Communication Access

The right and ability of all people to communicate and be understood, regardless of the mode or method of communication they use. Communication access encompasses the provision of supports, technologies, and environments that enable effective communication for people with…

Communication Access Realtime Translation(also: CART, Realtime Captioning, Stenographic Captioning)

A captioning service where a trained professional uses a stenographic keyboard to transcribe spoken language into text in real time, producing near-verbatim captions. CART provides the highest accuracy among live captioning methods and includes speaker identification, tone of…

Communication Asymmetry(also: Interaction Asymmetry, Communication Imbalance)

The imbalance in communication capabilities, speed, or modalities between conversation partners. In AAC contexts, communication asymmetry arises because AAC users communicate at 12-18 words per minute compared to 125-185 for typical speakers, creating fundamental differences in…

Communication Board(also: AAC Board, Symbol Board, Choice Board)

A low-tech or digital display of symbols, pictures, words, or phrases arranged on a surface that a person with complex communication needs can point to, touch, or select to express messages. Communication boards can be static (fixed vocabulary on a single page) or dynamic…