Glossary

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Design Psychology(also: Designer Cognition, Design Thinking Process)

The study of the cognitive processes, mental models, and decision-making strategies that designers employ during the product development process. In the context of accessibility, design psychology is relevant because accessibility guidelines and resources must align with how…

Design Saviorism

A problematic dynamic in design practice where nondisabled designers position themselves as rescuers of disabled people, seeking praise while attempting to fix something that is not broken. Design saviorism perpetuates power imbalances by centering the designer's perspective…

Design Sprint(also: Google Design Sprint)

A structured, time-constrained design methodology originally developed at Google Ventures that guides teams through five phases — Map, Sketch, Decide, Prototype, and Test — to rapidly solve design problems and validate ideas with real users. In accessibility contexts, design…

Design System(also: Component Library, UI Kit)

A collection of reusable components, patterns, guidelines, and assets that together define the visual language and interaction standards for a product or organization. Design systems typically include UI components, typography, color palettes, icons, illustrations, and…

Design Workshop(also: Design Session)

A structured session where participants collaborate to generate ideas, create prototypes, and provide feedback on designs. Design workshops are a common method in user-centered and participatory design for involving end users in the development process. However, traditional…

Design for All(also: DfA, Design pour Tous)

A European design philosophy that aims to create products, environments, and services usable by the widest possible range of people without adaptation or specialized design. Originating from the European Institute for Design and Disability (now Design for All Europe), this…

Design for Dynamic Diversity(also: D3, DDD)

A design paradigm proposed by Gregor, Newell, and Zajicek (2002) that explicitly accounts for the fact that human abilities are not static but change dynamically over time, particularly as people age. Unlike traditional approaches that design for a fixed "typical" user or treat…

Design for Social Accessibility(also: Social accessibility framework, DSA)

A design framework that extends traditional accessibility approaches by addressing not only the functional usability of technology but also the social contexts and implications of its use. Design for Social Accessibility is built on three tenets: incorporating users with and…

Design for User Empowerment(also: DfUE, Empowerment-Oriented Design)

A design philosophy that prioritizes giving users — particularly people with disabilities — the skills, tools, and agency to create, modify, and customize their own technology solutions rather than being passive recipients of products designed for them. Design for User…

Design justice

A framework that centers the perspectives and leadership of people most affected by design outcomes, challenging traditional design processes that often reinforce existing power structures. Coined and developed by Sasha Costanza-Chock, design justice draws on social movement…

Design probe(also: Technology probe, Cultural probe)

A research methodology in human-computer interaction where a prototype or artefact is deployed with participants not primarily to test usability, but to provoke reflection, surface unanticipated needs, and explore a design space. Unlike usability testing, which evaluates how…

Design space(also: Interaction modality)

A medium, physical or abstract, through which a user and a device exchange information. The visual design space uses sight (screens, displays), the sonic design space uses hearing (speech, earcons, music), and the haptic design space uses touch (braille displays, vibration,…

Design space properties

The characteristics of information within a design space, classified by the type of cognitive processing they require. Direct properties relate to perception and automatic processing — colour, brightness, and pitch are perceived immediately without conscious effort. Indirect…

Design space structure

A framework characterising how raw information is organised within a design space. Nesbitt classifies information conveyed through sensory channels as nominal (categorical, such as labels), quantitative (measurable, subdivided into temporal, spatial, and geographical), and…

Design-Based Research(also: DBR)

A collaborative, iterative research methodology used in education and human-computer interaction that develops theory and refines interventions through cycles of design, implementation, evaluation, and redesign in authentic real-world settings. DBR involves practitioners and…

Design-for-One(also: Design for One, Bespoke Design)

A design philosophy where systems are tailored to individual users rather than attempting to accommodate all users through a single universal solution. In contrast to universal design which seeks one solution for everyone, design-for-one creates systems that adapt to specific…

Designing with Friction(also: Friction by Design)

An HCI design stance, associated with Matthias Korn and Amy Voida, that argues for deliberately introducing friction into interactive systems to surface politics, provoke reflection, and enable democratic contention — rather than pursuing frictionless user experience as a…

Desire Paths(also: Desire lines)

A term from urban design describing the unofficial trails that pedestrians wear into grass or dirt when built sidewalks do not meet their needs - the visible trace of an infrastructure users have improvised for themselves. In accessibility design, the metaphor is used (e.g., by…

Detectable Warnings(also: Detectable Warning Surfaces, Tactile Warning Surfaces)

Detectable warnings are standardised tactile surface features installed on walking surfaces to alert people with visual impairments to hazards or transitions — most commonly the edge of a transit platform, the bottom of a curb ramp, or the junction between pedestrian and…

Deuteranomaly(also: Deutan Anomalous Trichromacy)

The most common type of colour vision deficiency, where the medium-wavelength (green) cone cells have a shifted sensitivity range. Deuteranomaly is a milder form of deutan CVD compared to deuteranopia, resulting in reduced ability to distinguish certain reds from greens. It…

Deuteranopia(also: Deutan Dichromacy, Green-Blind)

A type of colour vision deficiency caused by the complete absence of medium-wavelength (green) cone cells in the retina. Deuteranopia is the most common form of dichromacy, causing difficulty distinguishing red from green. Unlike protanopia, deuteranopia does not significantly…

Developmental Apraxia of Speech(also: Childhood Apraxia of Speech, CAS, DAS)

A motor speech disorder in which children have difficulty planning and coordinating the movements needed for speech, despite having no muscle weakness. Children with developmental apraxia of speech know what they want to say but their brains have difficulty coordinating the…

Developmental Delay(also: Developmental Disability, Global Developmental Delay)

A condition in which a child does not reach developmental milestones — such as motor skills, speech, social skills, or cognitive abilities — at the expected ages. Developmental delay may affect one or multiple areas of development and can be caused by genetic conditions,…

Developmental Disability(also: DD, Developmental Disabilities)

A group of conditions arising from impairments in physical, learning, language, or behavioral areas that begin during the developmental period, typically before age 22, and are expected to be lifelong. Developmental disabilities include intellectual disability, autism spectrum…

Developmental Learning Disorder(also: DLD, Specific Learning Disorder, Learning Disability)

A group of neurodevelopmental conditions that affect the acquisition and use of specific academic skills such as reading, writing, or mathematics. Developmental Learning Disorders include dyslexia (affecting reading), dysgraphia (affecting writing), and dyscalculia (affecting…

Developmental disability(also: Developmental disorder)

A group of conditions resulting from impairments in physical, learning, language, or behavioural areas that begin during the developmental period, are usually lifelong, and affect day-to-day functioning. Developmental disabilities include intellectual disability, autism spectrum…

Developmental screening(also: Early developmental screening, Autism screening)

A brief, standardized assessment process used to identify infants and young children who may be at risk for developmental delays or disabilities, including autism spectrum disorder. Common screening instruments include the Checklist of Autism in Toddlers (CHAT), the Screening…

Device Abandonment(also: Technology Abandonment, AT Abandonment)

The phenomenon where users stop using an assistive technology device after initial adoption. In AAC, abandonment rates are notably high and stem from multiple factors including devices that do not match users' communication strengths, poor customization, high cost, social…

Device Customization(also: AT Customization, Personalization)

The process of modifying or tailoring an assistive device to meet the specific physical, cognitive, or sensory needs of an individual user. Customization can range from simple adjustments like resizing a grip to complete redesigns of a device. 3D printing has made customization…

Device Fit(also: AT Fit, Assistive Device Fit)

The degree to which an assistive technology device matches the physical, cognitive, and contextual needs of its user. Good device fit encompasses physical dimensions, grip requirements, material properties, weight, and alignment with the user environment and daily routines. Poor…

Device Independence(also: Device-Independent Design, Input Agnostic Design)

A web design principle that ensures content and functionality are accessible regardless of the input device or interaction method used to access them. Device-independent design avoids assumptions about how users will interact with content — not relying solely on mouse events,…

Device Switching(also: Device Transition, Cross-Device Interaction)

The process of moving between different computing devices to complete tasks, such as switching from a smartphone to a laptop or tablet. For people with motor impairments, particularly wheelchair users, device switching presents significant accessibility barriers because it often…

Device-Dependent Event Handler(also: Device-Dependent Event, Mouse-Dependent Event Handler)

An event handler in web development that is triggered only by a specific input device, such as a mouse click or touch gesture, rather than being accessible through multiple input methods. Device-dependent event handlers create significant accessibility barriers because users who…

Dexter Model(also: Dexter Hypertext Reference Model)

A reference model for hypertext systems published in 1988 that defines the fundamental concepts of components, links, anchors, and presentation specifications. The Dexter Model was created as a superset description of what hypertext systems could be, with individual systems like…

Dexterity(also: Fine Motor Control, Manual Dexterity)

The ability to perform precise, coordinated movements with the hands and fingers, including gripping, pinching, typing, and manipulating small objects. Dexterity is distinct from gross motor function (large body movements) and varies widely among individuals with motor…

Dexterity Impairment(also: Dexterity Difference, Reduced Dexterity, Fine Motor Impairment)

A reduction in the ability to perform precise, coordinated movements with the hands and fingers, which can range from mild to severe and may be permanent, intermittent, or transient. Dexterity impairments can result from a wide range of conditions including arthritis, carpal…

Diabetic Retinopathy(also: DR)

A complication of diabetes that damages the blood vessels of the retina, potentially causing vision loss ranging from mild blurriness to complete blindness. Diabetic retinopathy can produce scattered and varied patterns of vision loss across the visual field, making it distinct…

Diagnostic Bias(also: Assessment Bias)

Systematic errors in the diagnostic process that lead to certain groups being more or less likely to receive a particular diagnosis based on characteristics unrelated to the condition itself, such as gender, race, age, or socioeconomic status. In ADHD, diagnostic bias has…

Diagnostic Overshadowing

A clinical phenomenon in which the symptoms or behaviours of a person with a disability are incorrectly attributed to their existing disability rather than being recognised as signs of a separate condition. In the context of intellectual and developmental disabilities (I/DD),…

Diagram Accessibility(also: Accessible Diagrams, Scientific Diagram Accessibility)

The practice of making visual diagrams — including scientific figures, flowcharts, organizational charts, and technical schematics — accessible to people with visual impairments, learning disabilities, or other conditions that affect visual processing. Diagram accessibility goes…

Dialog Act(also: Dialogue Act, Speech Act)

A classification label representing the communicative intention behind a spoken or written utterance in a conversational system. In the context of accessible technology, dialog acts are used to interpret what a user wants to accomplish when issuing voice commands — for example,…

Dialog Interface(also: Dialogue Interface, Conversational Interface)

A user interface paradigm in which interaction occurs through a structured exchange of prompts and responses, typically using speech or text. In assistive technology contexts, dialog interfaces present content and navigation options through audio prompts, allowing users to make…

Dialogue Design(also: Interaction Dialogue, User Dialogue Design)

Dialogue design in human-computer interaction refers to the structured planning of the conversational exchange between a user and a system, defining how input is accepted, how the system responds, and how errors are handled across interaction turns. In accessible interface…

Dialogue of Care(also: Care Dialogue, Care Communication)

The ongoing exchange of information, observations, and concerns between a person receiving care and their carers — whether professional, familial, or informal. In assistive technology and telecare contexts, the dialogue of care refers to the shared understanding that develops…

Diaphragmatic Breathing(also: Belly Breathing, Abdominal Breathing)

A breathing technique that emphasises movement of the abdominal wall and diaphragm during inspiration rather than the accessory muscles of the neck and shoulders. By engaging the diaphragm more fully, diaphragmatic breathing increases tidal volume, decreases respiratory…

Diarization(also: Speaker Diarization, Speaker Segmentation)

The process of automatically determining "who spoke when" in an audio or video recording by segmenting the audio stream and assigning each segment to a specific speaker. In accessibility contexts, diarization is critical for deaf and hard of hearing users who rely on captions or…

Diary Study(also: Diary Method, Experience Sampling)

A longitudinal research method in which participants record their experiences, behaviors, and reflections over an extended period (days to weeks) while interacting with a system or technology in their natural environment. In accessibility research, diary studies are particularly…

Dichoptic presentation(also: Dichoptic display, Dichoptic filtering, Dichoptic stimulation)

A technique in which different visual information is presented separately to each eye, typically using color-filtered glasses (red-cyan or red-green anaglyph), polarized lenses, or head-mounted displays. In clinical settings, dichoptic presentation is used as a therapeutic…

Dichromacy(also: Dichromatic Vision)

A category of colour vision deficiency in which one of the three types of cone cells is completely absent, reducing colour perception to two primary channels instead of three. The three forms are protanopia (missing red cones), deuteranopia (missing green cones), and tritanopia…

Dichromat(also: Dichromacy, Dichromatic Vision)

A person with colour vision based on only two types of functional cone cells in the retina instead of the typical three, resulting in a reduced ability to distinguish certain colours. Dichromats perceive colour in a two-dimensional colour space rather than the three-dimensional…