Glossary

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Focus+Context(also: Focus plus Context, Focus and Context)

A visualization interaction paradigm that integrates a detailed focus region and its surrounding context into a single unified view, rather than separating them. Techniques include fisheye views, semantic zooming, and lenses that distort or overlay content so users can see fine…

Foot-Based Interaction(also: Foot Input, Foot Gesture Interaction)

An interaction technique that uses foot movements and gestures as input for controlling digital devices. Foot-based interaction is particularly relevant for people with upper body motor impairments who have functional lower limbs but cannot use their hands, including people with…

Force Field(also: Haptic Force Field, Virtual Force Field)

In haptic interface design, a computational model that defines attractive or repulsive forces at each point in a two-dimensional workspace, used to represent graphical user interface elements as tactile objects. When a user moves a haptic pointing device through a force field,…

Free-Roam Locomotion(also: Room-Scale VR, Physical Locomotion)

A VR locomotion method where the user's real-world physical movement is directly mapped to movement in the virtual environment—walking forward in the real room moves the user forward in VR. While free-roam provides the most natural and immersive movement experience, it presents…

Frequency mapping(also: Pitch mapping, Frequency-position mapping)

A sonification technique that encodes spatial position or data values as changes in audio frequency (pitch), creating an intuitive correspondence between vertical position and pitch height — low positions produce low-frequency sounds and high positions produce high-frequency…

Functional Colour(also: Functional Color)

Functional colour is a design technique for auditory interfaces where visual colour distinctions are replaced with alternative identifiers — typically numbers or mnemonic labels — that convey the same categorical or grouping information through non-visual channels. For example,…

Gamification(also: Game-Based Learning)

The application of game design elements and principles in non-game contexts to increase engagement, motivation, and learning outcomes. In reading accessibility, gamification has been used in literacy development tools for children with disabilities, including reading therapy…

Gestural Input(also: Gesture-based Input, Touch Gestures)

Input methods that interpret finger movements on a touchscreen as commands, including taps, swipes, pinches, and multi-finger gestures. For blind users, gestural input must be performed without visual feedback, requiring consistent gesture recognition regardless of screen…

Gestural Interface(also: Gesture-Based Interface, Gestural Controller)

An input device or system that interprets body movements, hand gestures, or physical expressions as control signals for digital systems. In accessibility and music contexts, gestural interfaces are particularly relevant for d/Deaf and Hard of Hearing users who communicate…

Gesture Elicitation(also: User-Defined Gestures)

Gesture elicitation is a participatory design method where end users are asked to invent gestures for a set of device functions, rather than having gestures predetermined by designers or engineers. Participants are shown the effect of an action (such as zooming in) and asked to…

Gesture Elicitation Study(also: Gesture Elicitation, User-Defined Gestures)

A research methodology in which participants are presented with the effects or outcomes of actions (called referents) and asked to propose gestures they would naturally perform to trigger those effects. This approach captures user preferences and expectations rather than…

Gesture Input(also: Gestural Input, Gesture-Based Input)

A form of human-computer interaction where users perform physical movements—such as swipes, taps, pinches, or mid-air hand motions—to issue commands or provide input to a digital device. Gesture input is fundamental to touchscreen smartphones, tablets, and increasingly to…

Gesture Input(also: Gesture Recognition, Gesture-Based Interaction)

An input method that uses physical movements of the body — typically hands, fingers, arms, or head — to interact with digital systems. Gesture input includes touchscreen gestures (swipes, taps, pinches), mid-air gestures detected by cameras or motion sensors, and motion gestures…

Gesture Set Design(also: Gesture Vocabulary Design)

The process of selecting and defining a collection of gestures that users will perform to interact with a system, including decisions about which physical movements map to which functions. Effective gesture set design considers factors such as learnability, memorability,…

Gesture vocabulary(also: Gesture set, Interaction gesture repertoire)

The complete set of touch gestures recognized and used by a device or application, including single-stroke gestures (swipes, flicks), multistroke gestures (multi-tap, draw-then-tap), and multitouch gestures (pinch, rotate, two-finger swipe). As touchscreen interfaces evolve,…

Gesture-Based Interface(also: Gestural Interface, Gesture Recognition Interface)

An interaction system that interprets human gestures—such as hand movements, body poses, or finger motions—as input commands. Gesture-based interfaces can use cameras, accelerometers, touch surfaces, or wearable sensors to detect and interpret movement. In accessibility, they…

Gesture-based interaction(also: Gestural interface, Touchless interaction)

An interaction modality where users control technology through body movements, hand gestures, or postures detected by sensors such as depth cameras, rather than through traditional input devices like keyboards, mice, or touchscreens. Gesture-based interaction can benefit people…

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…

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…

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…

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…

Haptic Consent(also: Vibrotactile Consent)

A consent model in which the request for, agreement to, and revocation of consent are communicated through touch or vibration rather than speech. Haptic consent is motivated by accessibility: many neurodivergent people, Deaf and hard-of-hearing people, and people in high-emotion…

Haptic Feedback(also: Tactile Feedback, Touch Feedback)

Information conveyed through the sense of touch, typically using vibrations, force, or texture changes to communicate data or system states to a user. In accessibility, haptic feedback provides non-visual, non-auditory confirmation of actions and can convey spatial information,…

Haptic Feedback(also: Tactile Feedback, Haptics)

Technology that communicates information through the sense of touch, using vibrations, pressure, or motion applied to the user's body. In accessibility, haptic feedback provides a non-visual, non-auditory channel for conveying alerts, navigation cues, or interface responses —…

Haptic Icon(also: Hapticon)

A short, structured vibrotactile or force pattern designed to carry meaning in the same way a graphical icon or audio earcon does, allowing users to recognize a category of information — an alert, material, identity, or state — through touch alone. The concept generalizes…

Human-Machine Interface(also: HMI, Human-Computer Interface)

The point of interaction between a human user and a machine, system, or device, encompassing the hardware and software through which users communicate with and control technology. In the context of accessible design, HMIs include physical controls (buttons, levers, keypads),…

Human-Vehicle Interaction(also: HVI, Vehicle-pedestrian interaction)

The field studying how people communicate, negotiate, and coordinate with vehicles and their occupants — including drivers, passengers, and, increasingly, automated systems. Human-vehicle interaction encompasses internal interfaces (dashboards, voice assistants,…

Human-computer interaction(also: HCI, Human-machine interaction)

The interdisciplinary study of the design, evaluation, and use of interactive computing systems by humans, drawing on computer science, psychology, design, and social science. HCI research encompasses how people use technology, how interfaces should be designed for usability and…

Hybrid Interaction(also: Multimodal Hybrid Approach)

An interaction design approach that combines multiple input and output modalities, allowing users to switch between them based on task requirements, context, and personal preferences. In accessibility research, the "voice for speed, screen for verification" principle exemplifies…

Hybrid automaton(also: Hybrid state machine)

A computational model that combines discrete state transitions with continuous dynamics, used in interactive systems to govern object behaviours based on multiple users's simultaneous inputs. In collaborative virtual environments for autism intervention, hybrid automata control…

Imaginary Interface(also: Spatial Memory Interface, Empty-Handed Interaction)

An interaction paradigm where users interact with a virtual interface mapped to empty space or their own body, without any physical device in the interaction area. Users transfer their spatial memory of familiar device layouts (like a smartphone screen) to their palm or mid-air,…

Implicit Interaction(also: Implicit Input, Implicit Human-Computer Interaction)

Implicit interaction refers to user input that the system infers from natural behaviors not explicitly performed for the purpose of issuing commands, such as gaze, gait, posture, physiological signals, or ambient context. It contrasts with explicit interaction, where users…

In-situ Highlighting(also: In-situ Guidance, In-situ Instruction, On-screen Highlighting)

In-situ highlighting is a tutorial technique that overlays visual indicators directly on the live application interface to show the user exactly where to tap, look, or interact next - rather than describing the action in a separate text or video tutorial. Common implementations…

Information Hierarchy(also: Content Hierarchy, Information Architecture)

The organization and prioritization of information elements in an interface, determining what users encounter first and how content is structured for navigation. In accessibility, information hierarchy is crucial because screen reader users experience content sequentially rather…

Information Scent(also: Information Smell)

A concept from information foraging theory that describes the strength of cues in a user interface that indicate whether a particular path (link, button, menu item) will lead to desired information or functionality. Strong information scent means users can easily predict what…

Information wayfinding(also: Digital wayfinding, Information navigation)

The process of orienting oneself within and navigating through digital information spaces such as websites, applications, or documents, analogous to physical wayfinding through buildings or cities. For screen reader users, information wayfinding relies on structural cues like…

Input Exertion(also: Input Effort, Interaction Cost)

The physical and cognitive effort required to provide input to a digital system, including keystrokes, mouse movements, taps, and voice commands. For people with motor impairments, input exertion is a critical accessibility concern because even small inefficiencies — such as…

Input Modality(also: Interaction Modality, Input Method)

A distinct channel or method through which a user provides input to a computing system, such as touch, voice, gesture, gaze, or keyboard interaction. In accessibility contexts, supporting multiple input modalities is critical because users with different disabilities may need…

Input Redundancy

A design principle that provides multiple alternative ways to accomplish the same input action, ensuring that users can interact with a system regardless of their specific abilities. In VR accessibility, input redundancy means offering controller input alongside hand tracking,…

Interaction Framing(also: Narrative Framing, Framing (Interaction Design))

Interaction framing refers to the way a system positions the user's role and the meaning of their input, independent of the underlying mechanics. The same choice can be framed as completing a task ("select the appropriate response") or as taking a meaningful action inside a…

Interaction Paradigm(also: Interaction Method, Input Paradigm)

A model or approach for how users interact with a system, encompassing the input devices, techniques, and patterns of engagement. In VR, common interaction paradigms include controller-based input, hand tracking, gaze-based interaction, and voice commands. Each paradigm has…

Interactive Description(also: Dynamic Description)

A design approach for providing accessible descriptions of interactive digital content that updates in real time as users navigate and manipulate elements. Unlike static alternative text, interactive descriptions consist of two complementary structures: state descriptions that…

Interface Complexity(also: UI Complexity)

The degree of intricacy in a user interface, encompassing the number of elements, depth of navigation, variety of interaction patterns, and cognitive load required to accomplish tasks. For blind and low vision users, interface complexity is a significant accessibility barrier…

Isometric Gesture(also: Isometric Contraction Gesture)

An isometric gesture is a gesture in which a person activates their muscles without producing visible movement — the body position remains static while muscle tension changes. This contrasts with isotonic gestures, where visible hand or arm movement occurs over time. Isometric…

Joint Bilingual Navigation(also: Bilingual Form Navigation, Dual-Language Navigation)

An interface design approach that allows users to interact with digital content simultaneously in two languages through different modalities. In the context of Deaf accessibility, joint bilingual navigation enables a form or document to be navigated either through sign language…

Joystick Locomotion(also: Continuous Locomotion, Thumbstick Locomotion)

A VR locomotion method where users tilt a joystick or thumbstick on a controller to move continuously through the virtual environment while remaining physically stationary. This method is accessible for users who cannot physically walk but have sufficient hand motor control to…

Just-in-Time Prompting(also: Trigger-Based Prompting, On-Demand Visual Check)

A prompting technique for voice and video-capable AI models where the user pre-configures the AI with a role and task description, then uses a trigger phrase (such as "check now") to initiate an on-demand visual analysis of the current camera view. Developed as a workaround for…

Keyboard Accessibility(also: Keyboard Navigation, Keyboard Operability)

The principle and practice of ensuring that all functionality of a website, application, or digital interface can be accessed and operated using only a keyboard, without requiring a mouse, touchscreen, or other pointing device. Keyboard accessibility is foundational to web…

Kinematic Chain Theory(also: Guiard's Kinematic Chain, Asymmetric Division of Labor)

A theoretical framework developed by Yves Guiard describing how the two hands work together in bimanual tasks. The theory distinguishes between symmetric interactions (both hands perform the same movement) and asymmetric interactions (hands perform different complementary…