Glossary

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Haptic Magnetism(also: Force Attraction, Haptic Gravity)

A technique used in haptic interfaces where virtual attractive forces pull a haptic device (such as a stylus) toward nearby virtual objects, simulating a magnetic or gravitational effect. In accessible virtual environments, haptic magnetism helps blind users discover and reach…

Haptic Music Technology(also: Vibrotactile Music Systems, Haptic Music Interfaces)

Technologies that convey musical information through touch, typically using vibrotactile feedback to transmit sound properties such as rhythm, frequency, and amplitude to the body. Haptic music technology includes wearable devices like vibrotactile vests and jackets that allow…

Haptic Perception(also: Tactile Perception, Touch Perception)

The ability to perceive and interpret information through the sense of touch, including the detection of texture, shape, temperature, pressure, and vibration. Haptic perception is a primary information channel for blind and low vision people and is central to the use of…

Haptic Pointing Device(also: Force Feedback Mouse, Haptic Mouse, Force Feedback Pointing Device)

An input device that combines the pointing functionality of a mouse or stylus with the ability to generate physical forces that the user can feel through their hand. Unlike a standard mouse that provides no tactile information about screen content, a haptic pointing device can…

Haptic Rendering(also: Haptic display rendering)

The process of computing and outputting touch-based signals — forces, vibrations, textures, or friction — so that a user can perceive virtual or remote objects through the sense of touch. Haptic rendering covers kinesthetic rendering (force feedback via joysticks, exoskeletons,…

Haptic Technology(also: Haptics, Touch Technology)

Technology that creates tactile experiences through the application of forces, vibrations, or motions to the user, enabling interaction through the sense of touch. Haptic technologies range from simple vibration motors in smartphones to sophisticated force-feedback devices and…

Haptic Toolkit(also: Tactile Prototyping Toolkit)

A collection of physical materials designed to enable hands-on design and prototyping through touch rather than vision. In accessible design research, haptic toolkits are developed specifically for blind and low vision participants to create lo-fi prototypes of devices and…

Haptic User Interface(also: Haptic UI, Haptic Interface)

A user interface that communicates information through the sense of touch, enabling users to interact with virtual or digital objects by feeling their physical properties such as shape, texture, weight, temperature, and vibration. Haptic user interfaces typically employ…

Haptic Virtual Reality(also: Haptic VR, Feelable Virtual Environment)

Haptic virtual reality refers to virtual environments that incorporate touch-based feedback, allowing users to feel virtual textures, shapes, and objects through force-feedback devices. Unlike visual-only VR, haptic VR provides tactile and kinaesthetic information — resistance,…

Haptic Wearable(also: Haptic Wearable Device, Wearable Haptic Technology)

A body-worn electronic device that communicates information through touch sensations such as vibration, pressure, or temperature changes. In accessibility contexts, haptic wearables can serve as assistive technologies that convey information through tactile channels when visual…

Haptics(also: Haptic Technology, Haptic Feedback)

Technology that creates tactile sensations through vibrations, forces, or motions to simulate touch and physical interaction with digital content. In accessibility, haptics enables people who are blind or have low vision to perceive spatial information, navigate interfaces, and…

Hard of Hearing(also: HoH, HH)

A term describing people with hearing loss ranging from mild to severe who typically have some functional hearing, often with the assistance of hearing aids or other amplification devices. Unlike many Deaf individuals who identify with Deaf culture and use sign language, people…

Harm OCD(also: Harm Obsessions)

A subtype of OCD characterized by intrusive, unwanted thoughts about causing harm to oneself or others, despite having no desire or intention to act on these thoughts. People with harm OCD may experience distressing mental images of violence, fear that they might lose control…

Harm Reduction

An approach that prioritizes minimizing negative consequences of potentially risky behaviors rather than demanding complete abstinence or compliance with prescribed rules. In accessibility and disability contexts, harm reduction acknowledges that disabled people often face…

Hate Speech

Hate speech refers to expression that attacks, demeans, or calls for violence or discrimination against individuals or groups based on protected characteristics such as race, ethnicity, religion, national origin, gender, sexual orientation, or disability status. On digital…

Head Control(also: Head-Controlled Interface, Head Mouse, Head Pointer)

An alternative computer input device that translates head movements into cursor movements on screen, enabling people who cannot use their hands or arms to operate a computer. Head control systems typically use ultrasonic sensors, infrared tracking, or camera-based systems to…

Head Pointer(also: Head Mouse, Head Tracking Device)

An assistive technology input device that translates head movements into cursor movements on screen, allowing people who cannot use their hands or arms to control a computer. Head pointers can be physical devices (a stick or stylus mounted on a headband used to press keys) or…

Head Pointing(also: Head-Controlled Pointing, Head Mouse)

Head pointing is an alternative input method that maps head movements to cursor position on a computer screen, enabling hands-free mouse control. The user moves their head to direct the cursor, with the system translating head orientation or position into screen coordinates.…

Head Pose Estimation(also: Head Orientation Detection, Gaze Direction Estimation)

A computer vision technique that determines the orientation or direction a person's head is facing, typically classifying whether someone is looking towards or away from the camera. In accessibility contexts, head pose estimation can help blind users determine whether a passerby…

Head Tracking(also: Head Movement Tracking, Head-Controlled Input, Head Tracker)

An assistive technology input method that translates natural head movements into computer cursor control or other input actions. Head tracking systems use cameras, infrared sensors, or depth sensors to detect head position and orientation, allowing users with limited or no hand…

Head Wand(also: Head Pointer, Head Stick, Mouth Stick)

A head wand is an assistive input device consisting of a pointer attached to a headband or held in the mouth, allowing people with limited or no hand and arm function to operate a keyboard, touchscreen, or other controls using head movements. Head wands are commonly used by…

Head-Mounted Display(also: HMD, VR Headset, AR Headset)

A wearable device worn on the head that places a display in front of the user's eyes to present virtual or augmented content. HMDs range from fully immersive VR headsets (like Meta Quest) that replace the visual environment to AR glasses that overlay digital information on the…

Head-Mounted Display (HMD)(also: HMD, Head-Mounted Display, Smart Glasses)

A display device worn on the head that places visual content in front of one or both eyes. Head-mounted displays include AR smart glasses (like Vuzix Blade), VR headsets, and mixed reality devices. In accessibility applications, HMDs can present captions, sign language…

Head-based Pointing(also: Head Tracking, Head Mouse, Head-controlled Input)

An alternative input method that allows users to control an on-screen cursor by moving their head, typically tracked via a camera, infrared sensor, or inertial measurement unit. Head-based pointing is particularly valuable for people with motor impairments who cannot use…

Head-mounted display(also: HMD, Smart glasses, Head-worn display)

A wearable device that positions a display in front of one or both eyes, either overlaying digital content onto the real world (optical see-through) or replacing the visual field with a camera-captured and digitally processed view (video see-through). For people with low vision,…

Head-related transfer function(also: HRTF)

A response function that describes how sound from a specific point in space is filtered by the shape of the outer ear, head, and torso before reaching the eardrum. HRTFs are unique to each individual and are used in spatial audio rendering to create realistic 3D sound over…

HeadMaster(also: HeadMaster Plus)

An early head-pointing assistive technology device developed by Prentke Romich Company that translates head movements into mouse cursor movements on screen. The HeadMaster uses an ultrasonic sensor worn on the head (typically mounted on a headband or glasses) to track head…

Heading Navigation(also: Navigate by Headings)

A screen reader navigation strategy that allows users to jump between heading elements (h1-h6) on a webpage, bypassing intermediate content to quickly find sections of interest. Heading navigation is one of the most important strategies for efficient screen reader use, but its…

Heading Structure(also: Header Hierarchy, Heading Levels, Document Outline)

The hierarchical organization of headings (H1 through H6 in HTML) used to define the logical structure and sections of a document or web page. Proper heading structure is one of the most critical accessibility features for screen reader users, who rely on headings to skim…

Heading hierarchy(also: Heading structure, Heading levels)

The logical, nested structure of HTML heading elements (h1 through h6) that organizes web content into a navigable outline. A well-structured heading hierarchy uses heading levels sequentially without skipping levels, with a single h1 for the page title, h2 for major sections,…

Heading hierarchy(also: Heading structure, Heading levels, Document outline)

The logical structure created by using HTML heading elements (h1 through h6) in a nested, hierarchical order to convey the organisation of content on a web page. A proper heading hierarchy starts with a single h1 for the page title, with h2 elements for major sections, h3 for…

Heads-Up Display(also: HUD)

A transparent or overlay display that presents information in the user's direct line of sight without requiring them to look away from their current viewpoint. Originally developed for aviation, HUDs are widely used in virtual and augmented reality to attach interface elements —…

Health Data Visualization(also: Health Data Display, Patient Data Visualization)

The presentation of personal health information — such as blood glucose levels, blood pressure readings, activity data, or medication schedules — in visual formats including graphs, charts, trend lines, and indicators designed to help patients understand and manage their health…

Health Informatics(also: Medical Informatics, Clinical Informatics)

The interdisciplinary field concerned with the design, development, and use of information technology and systems to improve healthcare delivery, management, and outcomes. Health informatics encompasses electronic health records, clinical decision support systems, patient…

Health Literacy(also: Digital Health Literacy, eHealth Literacy)

The degree to which individuals can obtain, process, understand, and act on health information and services needed to make appropriate health decisions. In the digital context, health literacy extends to the ability to seek, find, understand, and appraise health information from…

Health Misinformation(also: Medical Misinformation, Health Disinformation)

False or misleading health-related information that is spread regardless of intent to deceive. On social media and video platforms, health misinformation about conditions like ADHD can include inaccurate symptom descriptions, unproven treatments, misleading diagnostic criteria,…

Health Monitoring(also: Remote Patient Monitoring, Health Surveillance)

The continuous or periodic collection of health-related data using sensors, wearables, or smart home technology to track an individual's wellbeing and detect problems. Health monitoring systems may track vital signs (heart rate, blood pressure), activity levels, medication…

Health-Related Impairment and Disability(also: HIID, Health-Related Impairments and Disabilities)

A category of impairments that arise as a consequence of health conditions, both chronic and acute, rather than from a traditionally defined disability. HIIDs are characterized by four properties: they are combinatorial (multiple low-intensity impairments that interact to create…

Healthcare Access(also: Healthcare Accessibility)

The ability of disabled people to obtain timely, appropriate, and respectful healthcare services. Healthcare access barriers include physical inaccessibility of medical facilities, communication barriers with providers, diagnostic overshadowing (where symptoms are attributed to…

Hearable(also: Smart Earbud, Smart Earphone)

A class of in-ear or over-ear wearable devices that combine audio playback with one or more sensors and on-device computing - microphones for ambient audio capture, inertial sensors, biosensors, and machine-learning accelerators - enabling features beyond passive listening.…

Hearcon(also: 3D Earcon)

An extension of the earcon concept that adds three-dimensional spatial audio properties to non-speech audio cues used in computer interfaces. While earcons are abstract synthesized sounds that represent interface events or objects, hearcons position these sounds in 3D space…

Hearing Aid(also: Hearing Aids)

An electronic device worn in or behind the ear that amplifies sound to assist people with hearing loss. Modern hearing aids include digital signal processing, directional microphones, and connectivity features like Bluetooth. While hearing aids improve access to speech and…

Hearing Aid(also: HA, BTE, Behind-the-Ear)

An electronic device worn in or behind the ear that amplifies sound for individuals with hearing loss. Modern hearing aids include features such as Bluetooth connectivity, directional microphones, and noise reduction. Behind-the-ear (BTE) models are among the most common styles.…

Hearing Aid Compatibility(also: HAC, HAC Rating)

Federal Communications Commission (FCC) requirements and ratings for telephones to work effectively with hearing aids and cochlear implants. HAC standards address acoustic coupling (how well the phone works with hearing aid microphones) and telecoil coupling (magnetic signal…

Hearing Impairment(also: Hearing Loss, Hard of Hearing)

A partial or total inability to hear sounds in one or both ears, ranging from mild to profound. Hearing impairment can be congenital or acquired, and may worsen with age (presbycusis). In digital accessibility, hearing impairment necessitates alternatives to audio content such…

Hearing Loss(also: Hearing Impairment, Hard of Hearing, Deafness)

A partial or total inability to hear sounds, ranging from mild hearing loss to profound deafness. Hearing loss can be congenital or acquired, and becomes increasingly common with age, affecting approximately one-third of people over 65. Digital accessibility for people with…

Hearing loss(also: Hearing impairment, Hard of hearing, Deafness spectrum)

A reduction in the ability to perceive sounds, occurring on a spectrum from mild (difficulty hearing soft sounds or speech in noisy environments) through moderate and severe to profound (inability to hear most sounds without amplification). Hearing loss may be unilateral (one…

Heart Rate Variability(also: HRV)

The variation in time intervals between consecutive heartbeats, reflecting the balance between sympathetic (stress response) and parasympathetic (rest and recovery) branches of the autonomic nervous system. HRV is used as an objective measure of stress, emotional state, and…

Heat Map(also: Heatmap, Attention Map, Gaze Map)

A data visualization technique that uses colour intensity to represent the distribution and density of user attention or interaction on a page or interface. In eye tracking research, heat maps aggregate fixation data from multiple users, with warmer colours (red, orange)…

Heavy Disguise

A research-ethics technique introduced by Amy Bruckman (2002) for handling quotes and user-generated content drawn from public online spaces. Under heavy disguise the researcher rephrases quotations, omits usernames and platform identifiers, and verifies (e.g., via search) that…