Glossary

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Green Space Accessibility(also: Outdoor Leisure Accessibility, Park Accessibility)

The design and adaptation of natural environments such as parks, gardens, forests, and countryside areas to be usable and enjoyable by people with disabilities. Green space accessibility encompasses multiple dimensions: accessible information for planning visits, navigable…

Grey Digital Divide(also: Gray Digital Divide, Age-Related Digital Divide)

The gap in technology adoption, usage, and digital skills between older adults and younger populations. While older adults may be interested in using technology for communication, health management, and entertainment, they often face barriers including interface complexity,…

Gricean maxims(also: Conversational maxims, Cooperative principle)

A set of principles proposed by philosopher Paul Grice that describe the implicit rules governing cooperative conversation: quantity (be informative but not over-informative), quality (be truthful), relation (be relevant), and manner (be clear and orderly). Gricean maxims are…

Grid Display(also: Symbol Grid, Grid-Based AAC)

A common AAC layout format that presents communication options as symbols, icons, or words arranged in a grid pattern of rows and columns. Grid displays are widely used in speech-generating devices and AAC apps, allowing users to construct messages by selecting individual…

Grid Navigation(also: Grid Accessibility, Table Navigation)

The ability to navigate through grid or table-based layouts using keyboard controls and assistive technologies. Calendar applications commonly use grid layouts to display weeks and months, which present significant accessibility barriers for screen reader users. Problems include…

Grid Recursion(also: Recursive Grid Navigation, Hierarchical Grid)

A navigation technique where a grid cell can be further subdivided into a finer sub-grid, allowing users to achieve progressively more precise positioning through successive levels of refinement. For example, a 3x3 top-level grid provides 9 positions; descending one level into a…

Grid-Based Cursor Control(also: Grid-Based Navigation, Grid Overlay Navigation)

A hands-free cursor positioning technique that overlays a numbered grid on the screen, allowing users to select a cell by voice command or other input to recursively zoom into smaller screen regions until the desired target is reached. Grid-based approaches reduce the vocabulary…

Grid-Based Interface(also: Grid Navigation Interface)

An interaction paradigm that divides a screen or workspace into a grid of cells, allowing users to navigate by specifying grid coordinates rather than precise pixel positions. Grid-based interfaces are particularly valuable for non-visual access because they provide a structured…

Grid-Based Navigation(also: Grid Navigation, Grid Cursor Control)

A speech-controlled cursor positioning technique that divides the screen into numbered regions, allowing users to select progressively smaller areas by speaking numbers until the cursor reaches the target location. This alternative input method enables people with upper-body…

Griefbot(also: Deadbot)

A griefbot (sometimes 'deadbot') is an AI chatbot trained on the written, voice or video communications of a deceased person, intended to let bereaved loved ones continue a simulated dialogue with them. Griefbots are a specific application of continuing-bonds practice and raise…

Gross Motor Function Classification System(also: GMFCS)

A standardized five-level classification system used to describe the gross motor function of children with cerebral palsy, based on self-initiated movement with emphasis on sitting, walking, and mobility. Level I indicates the highest function (walking without limitations),…

Gross Motor Movement(also: Gross Motor Skills, Gross Motor Control)

Large body movements involving the major muscle groups of the arms, legs, and torso, as opposed to fine motor movements that require precise control of small muscles in the fingers and hands. In assistive technology, the distinction between gross and fine motor abilities is…

Gross Motor Skills(also: Large Motor Skills, Gross Motor Function)

Motor skills involving large muscle groups that enable whole-body movements such as walking, running, jumping, climbing, and maintaining balance and posture. Unlike fine motor skills which involve precise small movements, gross motor skills provide the foundation for stability…

Ground Truth(also: Gold standard, Reference labels)

In machine learning, the labels treated as authoritative when training or evaluating a model - typically produced by human annotators or expert consensus and assumed to represent the 'correct' answer. Critical AI scholarship has shown that ground truth is socially constructed:…

Grounded Theory

A qualitative research methodology in which theory is systematically generated from data through iterative coding, categorization, and comparison rather than testing a pre-existing hypothesis. In accessibility and HCI research, grounded theory is commonly used to analyze…

Grounding(also: Grounding Techniques, Grounding Exercises, Self-Regulation)

A set of therapeutic and coping techniques used to help a person reconnect with the present moment and their physical surroundings during periods of emotional distress, anxiety, or trauma response. Grounding activities aim to strengthen the connection between mind and body and…

Group Narrative(also: Collaborative Storytelling, Co-Signing Performance)

A collaborative storytelling activity deeply rooted in Deaf culture and communities where two or more signers jointly perform a story using sign language, often with exaggerated and creative expression. In a typical group narrative, one person stands in front handling non-manual…

Groupware(also: Collaborative Software, Computer-Supported Cooperative Work Software)

Software designed to help multiple people coordinate, communicate, and collaborate on shared work. Groupware covers shared calendars and scheduling, document co-authoring, messaging, workflow, and shift-planning systems. Accessibility matters for groupware because these tools…

Growth mixture model(also: GMM, Latent class growth model)

A statistical method that identifies unobserved subpopulations (latent classes) within a dataset based on distinct patterns of change over time. In accessibility research, growth mixture models can reveal that a seemingly homogeneous user group actually contains distinct…

Guardianship(also: Legal Guardianship, Guardian, Caregiver Guardianship)

A legal arrangement in which a person (the guardian) is appointed to make decisions on behalf of another person who is deemed unable to make certain decisions independently, often due to intellectual disability, cognitive impairment, or age. In accessibility research,…

Guiard's Theory of Asymmetric Bimanual Action(also: Guiard kinematic chain model, Asymmetric bimanual action model)

Yves Guiard's 1987 model describing how the two hands typically take complementary, asymmetric roles in everyday manual tasks. The non-dominant hand sets a coarse spatial frame of reference that the dominant hand operates within, the non-dominant hand precedes the dominant hand…

Guide Dog(also: Seeing Eye Dog, Service Dog, Dog Guide)

A specially trained assistance animal that helps blind or visually impaired individuals navigate their environment safely. Guide dogs are trained to avoid obstacles, stop at curbs and steps, and navigate around barriers, enabling their handlers to travel more independently. As a…

Guide Runner(also: Sighted Guide Runner, Running Guide)

A sighted person who accompanies a blind or visually impaired runner during training or competition, providing verbal navigation cues and physical guidance typically through a tether connecting the two runners. Guide runners must match the ability level of the BVI runner,…

Guide-by-Pointing(also: Point-and-Ask, Hand-Guided Visual Query)

A prompting technique for multimodal AI assistants where a user extends their hand into the camera's field of view and asks the AI to identify what they are pointing at, or to provide spatial directions for moving their hand toward a specific item. This technique enables blind…

Guided Error Training(also: Error-Based Training, Productive Failure)

An instructional method where learners observe or experience common errors along with their corrections, rather than only seeing error-free demonstrations. Research shows this approach helps build more robust mental models of how systems work, improving knowledge transfer to new…

Guided Incremental Search(also: Step-by-Step Search, Faceted Browsing)

A web navigation pattern in which users are led through a series of small, sequential choices — such as selecting categories, subcategories, and filters — to progressively narrow search results toward a target. While this approach reduces the cognitive demand of each individual…

Guided Participation

Guided participation is a concept from Barbara Rogoff's developmental psychology describing how children learn through engaged collaboration with more experienced partners in everyday shared activities - not through formal instruction, but through side-by-side participation…

Guided Tour(also: Guided Tour Navigation, Linear Navigation Pattern)

A web navigation pattern that sequentially links content pages in a collection, allowing users to browse items one by one using next and previous controls rather than returning to an index page between each item. Guided tours reduce the cognitive and mechanical overhead of…

Gulf of Execution

A concept from Don Norman's theory of action describing the gap between a user's intention and the actions available to achieve that goal through an interface. When the gulf of execution is large, users struggle to figure out how to operate a system to accomplish their…

Gunning Fog Index(also: Gunning FOG, FOG Index)

A traditional readability formula developed by Robert Gunning in 1952 that estimates the years of formal education a reader needs to understand a text on first reading. It is calculated from average sentence length plus the percentage of "complex" words — words with three or…

Gyroscope(also: Gyro Sensor)

A sensor that measures rotational velocity around one or more axes, detecting how quickly a device is being turned or twisted. Combined with accelerometers in an inertial measurement unit, gyroscopes provide detailed motion tracking that enables gesture recognition, orientation…

HAAT Model(also: Human Activity Assistive Technology Model)

A conceptual framework for understanding and designing assistive technology systems that identifies four interconnected components: the human user, the activity being performed, the assistive technology itself, and the context in which the activity takes place. Developed by Cook…

HCI4D(also: Human-Computer Interaction for Development)

A subfield of human-computer interaction that focuses on designing and evaluating interactive technologies specifically for development contexts, addressing the needs of underserved and marginalized communities in low-resource settings. HCI4D research draws on methods from both…

HHS Usability Guidelines(also: Research-Based Web Design and Usability Guidelines, Usability.gov Guidelines)

A comprehensive set of evidence-based web design and usability guidelines published by the U.S. Department of Health and Human Services (HHS). The guidelines cover areas including homepage design, page layout, navigation, scrolling, headings, links, text appearance, content…

HIPAA(also: Health Insurance Portability and Accountability Act)

A 1996 United States federal law that establishes national standards for the protection of certain health information. HIPAA's Privacy Rule governs who may access protected health information (PHI), while its Security Rule mandates administrative, physical, and technical…

HSL(also: Hue Saturation Luminosity, HSL Color Model, HSB)

A colour model that represents colours using three components: Hue (the type of colour, such as red, green, or blue, expressed as a degree on a colour wheel from 0 to 360), Saturation (the purity or intensity of the colour, from grey to fully vivid), and Luminosity or Lightness…

HTML(also: HyperText Markup Language)

The standard markup language used to create and structure content on the World Wide Web. HTML uses elements (tags) to define the semantic structure of documents, including headings, paragraphs, links, lists, tables, forms, and images. Proper use of semantic HTML is fundamental…

HTML Canvas(also: Canvas API, Canvas Element)

An HTML element used to draw graphics on a web page via JavaScript, rendering content as a bitmap image rather than as structured DOM elements. Unlike SVG, canvas content is not inherently accessible to screen readers because it produces a flat pixel surface with no semantic…

HTML Frame(also: Frame, Frameset, IFrame)

An HTML element that divides a web page into multiple independent sections, each displaying a separate document. Framesets (using the frame and frameset elements) split the browser window into distinct panes, while inline frames (iframe) embed one document within another. Frames…

HTML Remediation(also: Accessibility Remediation, A11y Remediation)

The process of modifying HTML code to fix accessibility violations and bring web content into conformance with accessibility guidelines like WCAG. Remediation can involve adding missing attributes (alt text, form labels, ARIA roles), correcting semantic markup (proper heading…

HTML Table(also: Data Table, Web Table)

An HTML table is a structured element in web markup used to organize data into rows and columns. Tables are created using the table, tr (table row), th (table header), and td (table data) elements. For accessibility, data tables must include proper header markup (th elements…

HTML5 Track Element(also: <track> Element, Track Tag, HTML Track)

The HTML5 <track> element is used to specify timed text tracks for <video> and <audio> elements, providing a standardized way to associate captions, subtitles, descriptions, chapters, and metadata with media content. Each <track> element specifies a kind (captions, subtitles,…

HULOP(also: Human-scale Localization Platform)

An open-source indoor navigation platform originally developed by IBM Research to support blind navigation using Bluetooth Low Energy (BLE) beacon fingerprinting for localisation plus a topological map server for route planning and point-of-interest data. HULOP has been used as…

Hackability

A methodology and design philosophy for encouraging DIY assistive technology development in which disabled people, allies, and professionals collaboratively hack, adapt, and remix existing objects into personalized assistive solutions. Hackability events bring together makers…

Hackathon(also: Accessibility Hackathon, Makeathon, ATHack)

A time-limited event (typically hours to days) where participants collaborate intensively to design and build technology solutions, often as prototypes or proofs of concept. Accessibility hackathons specifically focus on creating assistive technologies, but they have been…

Halant(also: Virama, Hasanta)

A diacritical mark used in Indian (Indic) scripts to suppress the inherent vowel of a consonant, enabling the formation of consonant clusters or conjuncts. When a halant follows a consonant, it indicates that the consonant should combine with the following consonant rather than…

Hallucination(also: AI Hallucination, Confabulation)

In the context of AI and large language models, the generation of content that is plausible-sounding but not grounded in the input data or factual reality. Hallucinations pose a particular risk in accessibility applications such as captioning, audio description, or alt text…

HamNoSys(also: Hamburg Notation System)

A phonetic transcription system designed to represent the form of signs in any sign language. Developed at the University of Hamburg, HamNoSys captures detailed information about hand movements, handshapes, and body positioning using a standardised set of symbols. It is one of…

Hamburger Menu(also: Hamburger Icon, Menu Icon)

A UI pattern using three stacked horizontal lines (☰) to hide and reveal a primary navigation menu, most commonly on mobile interfaces. Accessibility considerations include the need for an accessible name (e.g., aria-label="Menu"), keyboard operability, proper focus management…

Hand Tracking(also: Gesture Tracking, Hand Gesture Recognition)

A technology that detects and tracks the position, orientation, and movements of a user's hands and fingers without requiring physical controllers, typically using cameras and computer vision algorithms. In extended reality, hand tracking enables hands-free interaction through…