Glossary

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Global Public Inclusive Infrastructure(also: GPII)

A framework and set of technologies designed to allow people with disabilities to automatically have their accessibility preferences and settings applied across any device, platform, or service they encounter. GPII enables portable user profiles that specify needs such as large…

Global South(also: Developing World, Majority World)

A term referring broadly to countries in Africa, Latin America, Asia, and Oceania that have been historically marginalized in global economic and political systems. In accessibility research, the Global South is significantly underrepresented — most studies recruit participants…

Global South Accessibility(also: Accessibility in Low-Resource Settings, Developing World Accessibility)

The study and practice of making technology, environments, and services accessible to people with disabilities in low- and middle-income countries. Over 80% of the world's one billion people with disabilities live in the Global South, yet most accessibility research and…

Global South accessibility(also: Accessibility in developing countries, Majority world accessibility)

The study and practice of accessibility in countries of the Global South (Africa, South and Southeast Asia, Latin America), where over 80% of people with disabilities live. Accessibility in these contexts is shaped by distinct socio-material conditions including limited built…

Global Symbols

A community-interest company and open symbol platform that hosts multiple pictogram libraries for AAC and Easy Read, supports translation into many languages, and provides an AI-assisted SymbolBuilder tool for generating new symbols. Global Symbols is widely used in projects…

Gloss(also: Sign Gloss, Gloss Notation)

A form of transliteration used in sign language research where written words from a spoken language (typically the dominant spoken language of the region, such as English) are used as labels to represent individual signs. Glosses are written in capital letters by convention…

Glyph Substitution(also: GSUB)

A typographic process in which one or more characters in a text are replaced with alternative visual forms (glyphs) based on context, language, or stylistic requirements. In OpenType fonts, the GSUB table defines rules for substitutions such as ligatures (combining two…

Goal Crossing(also: Crossing-Based Input, Crossing Interface)

An input technique where users select targets by moving through a boundary line rather than clicking within a target area. Research shows goal crossing can improve input performance for people with motor impairments by reducing the precision demands of target acquisition—users…

Goal-Setting Theory

A motivational theory developed by Edwin Locke and Gary Latham proposing that setting specific, challenging goals leads to higher performance than vague or easy goals. In the context of ADHD support, goal-setting theory underpins features in body doubling platforms like…

Goalball

A Paralympic team sport specifically designed for athletes with visual impairments. Two teams of three players attempt to roll a ball containing internal bells into the opposing team's goal while defenders listen for the ball to block it. All players wear blackout eyeshades to…

Gold-Standard Evaluation(also: Gold Standard, Reference Standard Evaluation)

An evaluation methodology in natural language processing and generation where system output is compared against a set of pre-established correct or ideal responses. In text-based systems, gold-standard strings are human-produced reference outputs that serve as benchmarks.…

Goldmann Perimetry(also: Goldmann Visual Field Test, Kinetic Perimetry)

Goldmann perimetry is a clinical technique for mapping the visual field — the total area a person can see while fixating on a central point. The test uses a moving stimulus of controlled size and brightness projected onto a white hemispherical bowl, with the examiner tracking…

GoodMaps

GoodMaps is an accessible indoor navigation platform that provides detailed indoor maps and turn-by-turn navigation for blind and low-vision users in buildings such as airports, transit stations, hospitals, and government offices. The system uses a combination of smartphone…

Goodness of Pronunciation(also: GOP, GOP Score)

A computational measure used in automatic speech recognition to assess how closely a spoken utterance matches expected pronunciation patterns. GOP scores are calculated by comparing phone sequences from unrestricted ASR against forced alignment to the actual word sequence. In…

Google Lighthouse(also: Lighthouse)

An open-source automated tool developed by Google for auditing web pages across multiple quality dimensions including performance, accessibility, best practices, and SEO. Lighthouse's accessibility audit checks a subset of WCAG criteria automatically, generating a score from 0…

Gorilla Arm(also: Gorilla-arm effect, Gorilla arm syndrome)

A well-documented ergonomic phenomenon in which sustained unsupported arm elevation — typical of mid-air touchscreen, vertical display, or extended reality (XR) gesture interaction — produces rapid shoulder fatigue, pain, and performance decline. The term captures the ache and…

Gorilla Arm Syndrome(also: Gorilla Arm, Gorilla Arm Effect)

Fatigue, pain, and discomfort in the arms and shoulders caused by prolonged use of interfaces that require sustained arm elevation without support. The term originates from early touchscreen computing and has become particularly relevant in virtual and mixed reality, where users…

Government Digital Accessibility(also: Public Sector Accessibility, E-Government Accessibility)

The requirement and practice of ensuring that government websites, online services, documents, and digital tools are accessible to all citizens, including those with disabilities. Many countries have enacted legislation mandating government digital accessibility, such as Section…

Grab Bar(also: Safety Rail, Support Bar, Handrail)

A rigid, wall-mounted bar designed to provide support and stability for people who need assistance maintaining balance, transferring between positions, or preventing falls. Grab bars are most commonly installed near toilets, bathtubs, and showers, but may also be placed in…

Graceful degradation(also: Graceful degradation)

A design strategy in which web content built with newer or advanced technologies continues to function and remain accessible when those technologies are not supported by a user's browser or assistive technology. Under WCAG 2.0, technologies that are not accessibility-supported…

Grad-CAM(also: Gradient-weighted Class Activation Mapping)

A widely used explainable AI technique, introduced by Selvaraju et al. in 2017, that produces a class-discriminative heat map over an input image by weighting convolutional feature maps by the gradient of the target class score. Grad-CAM and its variants (SmoothGrad-CAM,…

Grade 1 Braille(also: Uncontracted Braille, Alphabetic Braille)

The basic level of braille in which each letter, number, and punctuation mark is represented by its own distinct braille cell, with no abbreviations or contractions. Grade 1 braille is typically used by beginning braille learners and for labeling purposes. While straightforward…

Grade 2 Braille(also: Contracted Braille)

The standard form of braille used in most published materials, which employs contractions — single braille characters or short groups of characters that represent common words, letter combinations, or word parts. Grade 2 braille is more concise than Grade 1, reducing reading and…

Grammaticality(also: Grammatical correctness, Grammatical acceptability)

The degree to which a sentence conforms to the grammatical rules of a language. In accessibility and NLP research, grammaticality is typically assessed via a 5-point Likert subjective judgement (e.g., "This sentence is grammatically correct") and is used as a component of…

Graph(also: Node-Edge Diagram, Network Diagram)

A data structure and visual representation consisting of nodes (vertices) connected by edges (links) that represent relationships between entities. In computer science and mathematics, graphs are used to model networks, hierarchies, flowcharts, and many other relational…

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…

Graph Literacy(also: Graphical Literacy, Graphicacy)

The ability to read, interpret, and construct graphs and other visual data representations. Graph literacy is a critical component of STEM education and is often tested as part of mathematics and science standards. For students with visual impairments, developing graph literacy…

Graph theory

A branch of mathematics that studies the relationships and connections between objects in an abstract sense. Graphs consist of nodes connected by edges, and can model a wide range of structures: roads connecting at intersections, books arranged by subject in a library, or web…

Grapheme

The smallest unit of a writing system, typically a letter or group of letters that represents a single phoneme (sound). For example, the word "ship" contains three graphemes: <sh>, <i>, and <p>. Understanding grapheme-phoneme correspondence — how written letters map to spoken…

Graphic Accessibility(also: Image Accessibility, Visual Content Accessibility)

The practice of making graphical content — including charts, diagrams, maps, photographs, and illustrations — perceivable and understandable by people who cannot see them. Graphic accessibility encompasses a range of techniques from simple alternative text descriptions to…

Graphic Captions(also: Visual Captions, Animated Captions)

A captioning approach that uses visual elements such as GIFs, animated stickers, icons, or emojis to represent sounds in audio-visual content, as an alternative or complement to traditional text-based bracket notation. Graphic captions can convey additional information about a…

Graphic Input Device(also: Drawing Input Device, Graphic Tablet)

A hardware device used to input and manipulate visual graphics on a computer, including digital drawing pads (digitizer tablets), styluses, mice, trackballs, touchscreens, and specialized assistive devices. For artists with upper limb motor impairments, the shape, size, pressure…

Graphic Score(also: Graphical Notation, Visual Music Score)

A form of musical notation that uses visual symbols, shapes, colors, and spatial arrangements rather than traditional staff notation to represent musical ideas and instructions. Graphic scores communicate musical concepts through visual means that can be more accessible to…

Graphic Transcription(also: Image Transcription, Accessible Graphic Transcription)

The process of converting visual graphics (charts, maps, floor plans, diagrams) into formats accessible to blind and visually impaired users, such as tactile graphics, audio descriptions, or interactive multimodal representations using sonification and speech. Graphic…

Graphicacy(also: Graph Literacy, Visual Literacy)

The ability to read, interpret, and communicate information presented in graphs, charts, maps, and other visual representations of data. Graphicacy is considered a foundational literacy alongside reading, writing, and numeracy. It involves three progressive stages: reading the…

Graphical Authentication(also: Graphical Password, Picture Password)

An authentication method that uses images, patterns, or visual elements instead of text-based passwords. Graphical authentication leverages human visual memory, which is generally stronger than verbal memory for recognition tasks. Types include recognition-based systems…

Graphical Model(also: Visual Model, Graphical Representation)

In educational and accessibility contexts, a visual representation system that uses shapes, colours, spatial relationships, and physical manipulation to convey abstract concepts. Graphical models for mathematics represent numbers as groups of objects whose size corresponds to…

Graphical Password(also: Picture Password, Visual Password)

An authentication method that uses images instead of text, requiring users to either recognize previously selected images (recognition-based) or recall specific points on an image (recall-based). Graphical passwords were designed to leverage visual memory, which is often…

Graphical Semantic Enhancement(also: Semantic Graphics, Labeled Graphics)

The practice of enriching graphical objects with meaningful text labels, descriptions, and metadata so that they can be understood non-visually. In accessible drawing and diagramming tools, graphical semantic enhancement allows users to assign descriptive labels to shapes,…

Graphical User Interface(also: GUI)

A type of computer interface that uses visual elements such as windows, icons, menus, and pointers to allow users to interact with software, as opposed to text-based command-line interfaces. GUIs present significant accessibility challenges for blind and low-vision users because…

Graphical User Interface(also: GUI, WIMP Interface)

A visual interface paradigm based on windows, icons, menus, and pointer (WIMP) interaction, which became dominant in personal computing from the late 1980s onward. GUIs represented a major accessibility challenge when they replaced text-based command lines: screen readers…

Graphical perception(also: Chart perception, Visual data perception)

The cognitive process by which people extract quantitative information from visual data representations such as charts, graphs, and maps. Graphical perception involves comparing positions, lengths, areas, angles, and colours to make judgements about data values and…

Graphics Tablet(also: Drawing Tablet, Pen Tablet, Digitiser Tablet)

An input device consisting of a flat surface on which a user draws or points with a stylus to interact with a computer. Graphics tablets translate the position and pressure of the stylus into cursor movements on screen. For users with motor impairments who find a mouse difficult…

Graphviz(also: DOT, Graphviz DOT)

An open-source graph visualization software suite that renders structural representations of graphs and networks from the DOT text specification language. DOT files describe nodes, edges, attributes, and layout hints, which Graphviz layouts engines (dot, neato, fdp, circo,…

Grasp Aperture(also: Hand Aperture, Finger Aperture)

Grasp aperture is the distance between the thumb and opposing finger(s) as the hand opens to receive an object during a reach. It scales with perceived object size, peaks before contact at a value typically larger than the object itself, and then closes to grip - a well-studied…

Grasp Recognition

Technology that detects and interprets how a user holds, grips, or manipulates objects, typically through sensors in VR controllers or camera-based hand tracking. In VR accessibility, grasp recognition is relevant because it can enable more natural object manipulation in virtual…

Graspable Interface(also: Graspable User Interface)

A graspable interface is a type of tangible user interface in which users interact with a computer system by physically grasping and manipulating real-world objects that are tracked by the system, typically through camera-based image processing or embedded sensors. Unlike…

Gravity Well(also: Target Attraction, Sticky Targets, Snap-to-Target)

An interaction filtering technique that warps the cursor space around interactive targets (such as buttons or links), creating attractive basins that pull the cursor toward the nearest target. This makes it easier for users with motor impairments to select small or distant…

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,…