Glossary
Searchable terminology from accessibility, web standards, and related fields.
6660 terms — page 23 of 333
- Alphabet Board (Letter Board, Spelling Board, Communication Board)
- A low-technology communication tool displaying letters of the alphabet that enables people who cannot speak to spell out words and messages by pointing to, gazing at, or otherwise indicating individua…
- Alt Text (Alternative Text, Alt Attribute, Image Description)
- A textual description of an image that is embedded in the HTML code and read aloud by screen readers, providing blind and low vision users with information about visual content. Effective alt text is …
- Alt Text Authoring (Alt Text Writing, Image Description Authoring)
- The process of composing alternative text descriptions for digital images, undertaken by content authors, developers, or dedicated accessibility specialists. Research has identified several barriers t…
- Alt text (Alternative text, Text alternative)
- A textual description of non-text content (primarily images) provided via the HTML alt attribute, read by screen readers and displayed when images cannot be loaded. Required by WCAG Success Criterion …
- Alternative Input Device (Alternative Input, Adapted Input, Alternative Access)
- Any computer input device used in place of a standard keyboard and mouse by people who cannot operate conventional input hardware due to physical, motor, or other disabilities. Alternative input devic…
- Alternative Input Method (Alternative Input, Non-Standard Input)
- Any method of providing input to a computer or device that differs from the conventional keyboard, mouse, and touchscreen interfaces. Alternative input methods are essential for people with motor, sen…
- Alternative Text (Alt Text, Alt Attribute)
- Text associated with an image that serves the same purpose and conveys the same essential information as the image. Alternative text is a fundamental web accessibility requirement specified in WCAG, e…
- Alternative input device (Alternative access method, Switch access)
- Any input method that replaces or supplements standard keyboard, mouse, or joystick interfaces to enable people with motor impairments to operate computers, wheelchairs, and other technology. Examples…
- Always-On Computing (Always-available computing, Continuous computing)
- A model of interaction in which computing devices — particularly wearables such as smartwatches, AR glasses, and fitness trackers — remain continuously active and accessible throughout the day rather …
- Alzheimer's Disease (Alzheimer's, AD)
- A progressive neurodegenerative disease and the most common cause of dementia, accounting for 60-80% of cases. Alzheimer's disease causes gradual decline in memory, thinking, and reasoning skills, eve…
- Amazon Alexa (Alexa, Echo)
- A cloud-based voice assistant developed by Amazon, available on Echo smart speakers, Echo Show smart displays, and third-party devices. Users interact with Alexa through wake-word-activated voice comm…
- Amazon Mechanical Turk (AMT, MTurk, Mechanical Turk)
- A crowdsourcing marketplace operated by Amazon that enables individuals and businesses to distribute tasks (called Human Intelligence Tasks or HITs) to a distributed workforce who complete them remote…
- Ambient Audio (Ambient Sound, Environmental Audio, Background Audio)
- The background sound of an environment — voices, traffic, water, wind, music, birdsong — captured incidentally rather than as the main focus of a recording. In accessible photography and audiophotogra…
- Ambient Display (Ambient Interface, Peripheral Display)
- A display or interface that communicates information through subtle environmental changes — such as colour shifts, lighting changes, or gentle sounds — that can be perceived at the periphery of a user…
- Ambient Intelligence (AmI)
- An environment enriched with networked, sensor-equipped devices that are sensitive and responsive to the presence and needs of people within it. Ambient intelligence systems anticipate user requiremen…
- Ambient assisted living (AAL, Smart home assistive living)
- Technology systems embedded in the home environment — including sensors, microphones, and smart devices — that monitor and support older adults or people with disabilities to live independently and sa…
- Ambiguous Loss
- Ambiguous loss, a concept articulated by Pauline Boss, is 'a situation of unclear loss that remains unverified and thus without resolution'. Boss distinguishes two types: physical loss where someone i…
- Ambiguous keyboard (T9 input, Multi-tap disambiguation)
- A text entry method in which multiple letters are mapped to each physical key, requiring disambiguation algorithms (typically dictionary-based) to determine the intended word from the sequence of key …
- Ambisonics (Ambisonic audio, Ambisonic sound)
- A full-sphere surround sound technique that captures and reproduces audio from all directions — including above and below the listener — using a spherical harmonic representation of the sound field. O…
- Amblyopia (Lazy eye)
- A neurodevelopmental vision disorder in which one eye has reduced visual acuity that cannot be fully corrected with glasses or contact lenses, caused by abnormal visual development in early childhood.…