Glossary

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Blackboard Ally(also: Ally)

A commercial accessibility-checking and alternative-format-generation service from Anthology (Blackboard) that integrates with learning management systems such as Blackboard Learn, Canvas, Moodle, and Brightspace. Ally scans uploaded course materials, reports accessibility…

Blended Learning(also: B-Learning, Hybrid Learning, Mixed-Mode Learning)

An educational approach that combines online digital media and methods with traditional face-to-face classroom activities. Blended learning integrates the flexibility and self-pacing of e-learning with the social interaction and immediacy of in-person instruction, allowing…

Blendshape(also: Morph Target, Shape Key)

A 3D animation technique that defines specific facial configurations (such as a smile, raised eyebrow, or open mouth) as target shapes, which can be blended together at varying intensities to create complex facial expressions. In sign language avatar systems, blendshape…

Blind(also: Blindness)

A visual impairment severe enough that a person cannot use vision as their primary means of perceiving information, typically defined legally in the United States as best-corrected visual acuity of 20/200 or worse in the better eye, or a visual field of 20 degrees or less.…

Blind Education(also: Education for the Blind, Visual Impairment Education)

Educational practices, methods, and systems designed to provide equitable learning opportunities for students who are blind or have low vision. Blind education encompasses specialized schools for the blind, mainstream inclusive settings with support services, and the use of…

Blind Epistemology

Ways of knowing and understanding the world as a blind person, which are fluid, relational, and shaped by touch, sound, memory, spatial familiarity, and social interaction rather than visual perception. Blind epistemology recognizes that blind people develop rich, valid…

Blind Hockey(also: Visually Impaired Hockey, VI Hockey)

An adapted form of ice hockey designed for players who are blind or have low vision. The sport uses a larger, oversized puck containing ball bearings that rattle when the puck moves, allowing players to track it by sound. Players are classified by vision level, with some wearing…

Blind Navigation(also: Non-visual navigation, Navigation for blind people)

The subfield of navigation research and assistive technology that addresses how people who are blind or have low vision find their way through indoor and outdoor environments without relying on sight. Solutions range from the white cane and guide dog to smartphone apps, BLE…

Blind Photography(also: Photography by Blind People)

The practice of photography by individuals who are blind or have low vision, challenging assumptions that photography is an exclusively visual medium. Blind photographers use a range of strategies including spatial memory, sound cues, tactile markers, AI-powered camera…

Blind Sports(also: Visually Impaired Sports)

Athletic activities designed for or adapted to enable participation by people who are blind or have low vision. These sports rely on non-visual cues, particularly sound, to make gameplay accessible — for example, blind hockey uses a puck with ball bearings inside to produce…

Blind and Low Vision(also: BLV, Vision Impairment, Visual Impairment)

A broad term encompassing the spectrum of vision loss from partial sight (low vision) to complete blindness. People who are blind or have low vision experience varying degrees of visual function, and their technology needs differ accordingly. Low vision users may benefit from…

Blind and Visually Impaired(also: BVI, Blind and low vision, BLV)

An umbrella term used in accessibility research and practice to encompass people whose vision is significantly reduced, from partial low vision (for example, reduced acuity, contrast sensitivity, or field of view) through total blindness. The term includes people who are…

Blind-Perspective Training(also: Non-Visual Training, Blindfold Training)

An educational and vocational training approach where all learners, regardless of their level of functional vision, are taught skills using non-visual techniques such as touch, hearing, and proprioception. In this model, sighted trainees may be encouraged to wear a blindfold to…

BlindSquare

A GPS-based iOS accessibility app designed for people who are blind or have low vision, providing spoken information about the surrounding environment — nearby points of interest, intersections, street names, and compass direction — drawn from OpenStreetMap and Foursquare data.…

Blindness(also: Total Blindness, Visual Blindness)

A condition of having no functional vision or light perception, requiring entirely non-visual means of accessing information and navigating the environment. Blind users typically rely on screen readers, braille displays, audio descriptions, and tactile materials to access…

Blindness(also: Blind, Total Blindness, Complete Vision Loss)

A condition characterised by the complete or near-complete absence of functional vision, ranging from no light perception to minimal light awareness that cannot be used for practical tasks. Blind individuals typically rely on non-visual senses and assistive technologies such as…

Blindness and Low Vision(also: BLV, visual impairment, vision impairment)

Blindness and low vision (BLV) collectively describes the spectrum of significant visual impairment ranging from complete absence of sight to partial sight loss that cannot be fully corrected with standard glasses or contact lenses. The World Health Organization defines low…

Blissymbols(also: Blissymbolics, Bliss Language)

A symbolic language created by Charles K. Bliss, consisting of several hundred basic symbols that can be combined to create new meanings. Unlike pictographic symbol sets where each image represents a specific word, Blissymbols are ideographic — they represent concepts rather…

Block-Based Programming(also: Visual Block Programming, Block Coding, Blocks-Based Programming)

A programming paradigm where users create code by selecting and connecting visual blocks that snap together like puzzle pieces, rather than typing text-based syntax. Each block represents a programming construct such as a loop, conditional, variable assignment, or function call.…

Blockchain(also: Distributed Ledger, Distributed Ledger Technology, DLT)

A blockchain is a distributed, append-only digital ledger in which records (blocks) are cryptographically linked and replicated across a decentralized network of nodes. No single party controls the data; once written, records are extremely difficult to alter. In accessibility…

Blocks-Based Programming(also: Block Programming, Visual Block Programming, BBPE)

A programming paradigm designed to introduce coding concepts to beginners — particularly children — by representing code as visual, interlocking blocks that are dragged and dropped to construct programs, rather than requiring typed syntax. Popular environments include Scratch,…

Blocks4All

An accessible touchscreen-based block-based programming environment designed for students with visual impairments. Blocks4All enables drag-and-drop-like programming interactions on touchscreen devices with screen reader support, making it one of the few on-screen block-based…

Blood Oxygen Saturation(also: O2sat, SpO2, Oxygen Saturation)

The percentage of hemoglobin in the blood that is bound to oxygen, typically measured non-invasively using a pulse oximeter. Normal blood oxygen saturation is generally 95-100%, and levels below 88-90% are considered clinically concerning and may indicate hypoxemia (dangerously…

Bloom's Taxonomy

A hierarchical framework originally proposed by Benjamin Bloom in 1956 and later revised, classifying educational learning objectives into levels of cognitive complexity: remembering, understanding, applying, analyzing, evaluating, and creating. In accessibility education,…

Blue Cone Monochromatism(also: BCM, S-cone Monochromacy)

A rare inherited vision condition in which only the blue (short-wavelength) cones function, resulting in severely reduced color vision, reduced visual acuity, photophobia, and nystagmus. Affected individuals see the world in shades of blue and yellow and typically benefit from…

Bluetooth(also: BLE, Bluetooth Low Energy)

A short-range wireless communication standard used to exchange data between devices over distances of up to approximately 30 metres. In accessibility, Bluetooth is widely used in assistive technology: hearing aids use Bluetooth to stream audio directly from phones and…

Bluetooth Beacons(also: BLE Beacons, iBeacons, Bluetooth Low Energy Beacons)

Small wireless transmitters that use Bluetooth Low Energy (BLE) to broadcast signals to nearby smartphones and other devices. In accessibility contexts, Bluetooth beacons are deployed in indoor environments to support wayfinding and navigation for blind and visually impaired…

Bluetooth Foot Pedal(also: Page Turn Pedal, Wireless Foot Pedal)

A wireless input device operated by foot that connects to tablets, computers, or specialized music-reading hardware via Bluetooth to enable hands-free page turning of digital music scores. Bluetooth foot pedals are particularly valuable for musicians who cannot take their hands…

Bluetooth Low Energy(also: BLE, Bluetooth LE, Bluetooth Smart)

A wireless communication technology designed for short-range data transmission with minimal power consumption. In accessibility contexts, BLE is widely used for indoor positioning and wayfinding systems through small transmitter devices called beacons. When a smartphone detects…

Bluetooth Low Energy Beacon(also: BLE Beacon, iBeacon, Bluetooth Beacon)

A small, low-power wireless transmitter that broadcasts Bluetooth Low Energy (BLE) signals at regular intervals. In accessibility contexts, BLE beacons are widely used for indoor navigation systems for people with visual impairments, as GPS does not work reliably indoors. By…

Bluetooth beacon(also: BLE beacon, iBeacon)

A small wireless transmitter that uses Bluetooth Low Energy (BLE) to broadcast signals to nearby devices, enabling indoor positioning and proximity detection. In accessibility applications, beacon networks deployed throughout buildings allow navigation apps to determine a user's…

Blurred Vision Simulation(also: Vision Simulation, Low Vision Simulation)

A technique used in accessibility evaluation where evaluators simulate the visual experience of people with reduced visual acuity by artificially blurring their view of a website or application. Methods include using low vision simulation glasses (commercially available from…

Board Game Accessibility(also: Tabletop Game Accessibility)

The practice of making physical board games, card games, and tabletop games playable by people with disabilities. Most commercial board games rely heavily on visual information — printed text, colors, visual textures, and spatial layouts — making them inaccessible to blind and…

Bobby(also: Bobby Worldwide, Watchfire Bobby)

Bobby was one of the earliest and most widely used automated web accessibility testing tools, developed by the Center for Applied Special Technology (CAST) and later acquired by Watchfire (subsequently IBM). Launched in the mid-1990s, Bobby checked web pages against WCAG 1.0…

Bodily Autonomy

The right of individuals to make decisions about their own bodies, including how they use their bodies for work, what medical treatments they receive, and how they manage their physical and mental health. In disability contexts, bodily autonomy is frequently compromised through…

Body Awareness(also: Body Schema, Body Image)

The understanding of one's own body including its structure, posture, position in space, and relationship to the environment. Body awareness encompasses both the physical sense of where body parts are (proprioception) and the cognitive understanding of body shape, proportions,…

Body Doubling(also: Parallel Working, Co-Working for Focus)

A productivity and focus strategy commonly used by people with ADHD and other executive function challenges, where having another person present — physically or virtually — helps with task initiation and sustained attention. The other person does not need to assist with the…

Body Ownership Illusion(also: BOI)

A perceptual phenomenon in virtual reality where users perceive a virtual body or avatar as their own, experiencing it as an extension of their physical self. This illusion is fostered when the virtual representation performs the same actions as the user's actual body, such as…

Body Sheet(also: Body Map, Body Mapping)

A body sheet is an outline drawing of the human body (typically front, back, and side views) used as a canvas onto which participants map bodily sensations, emotions, or symptoms. Originating in art therapy and physiotherapy pain-mapping practice, body sheets have been adopted…

Body-Centric Design

Design approaches in technology that center on the user's physical body as the primary means of interaction, such as VR systems that rely on body tracking, gestures, and physical movement. While body-centric design can create natural and intuitive interactions, it inherently…

Body-Powered Prosthesis(also: Cable-Operated Prosthesis, Mechanical Prosthesis)

A body-powered prosthesis is a type of prosthetic device that uses the wearer's own body movements to operate a mechanical function, typically through a cable-pull system. In upper-limb devices like those produced by the e-NABLE community, wrist flexion pulls cables that cause…

Bodymind

A concept from disability studies, introduced by Margaret Price and widely adopted by disability scholars and activists, referring to the inseparable integration of body and mind as a single entity. The term rejects the Cartesian dualism that separates physical and mental…

Bodymind Barrier(also: Bodymind Access Barrier)

A type of access barrier where performing a task leads to an undesirable physical or mental state, such as pain, fatigue, nausea, dizziness, anxiety, or sensory overload. The task may be technically completable without distress, but existing approaches cause the person's…

Bodystorming(also: Embodied Brainstorming)

A participatory design method where participants physically act out scenarios, interactions, or use cases using their bodies rather than paper prototypes or verbal descriptions. In accessibility research, bodystorming allows designers and users with disabilities to…

Bone Conduction(also: Bone Conduction Headphones, Bone Conduction Audio)

A method of transmitting sound vibrations through the bones of the skull directly to the inner ear, bypassing the outer and middle ear. Bone conduction headphones rest on the cheekbones or temples rather than covering or inserting into the ears, leaving the ear canals open to…

Bone Conduction Headphones(also: Bone Conducting Headphones, Bonephones)

Audio devices that transmit sound through the bones of the skull directly to the inner ear, bypassing the outer and middle ear. Unlike traditional headphones, bone conduction headphones leave the ear canal open, allowing users to hear environmental sounds while receiving audio…

Bone Conduction Headset(also: Bone Conduction Headphones, Bone Conduction Audio)

An audio device that transmits sound vibrations through the bones of the skull directly to the inner ear, bypassing the outer and middle ear and leaving the ear canal open. For people who are blind or have low vision, bone conduction headsets are particularly valuable during…

Bone conduction(also: Bone conduction hearing, Bone anchored hearing)

Bone conduction is a method of sound transmission that delivers audio vibrations through the bones of the skull directly to the inner ear, bypassing the outer and middle ear. Bone conduction technology is used in hearing aids and headphones designed for people with conductive…

Bone conduction headphones(also: Bone conduction earphones, Bone conduction audio)

Audio devices that transmit sound through vibrations on the skull bones rather than through the ear canal, leaving the ears open to ambient environmental sounds. For people with visual impairments using navigation assistants, bone conduction headphones are essential for…

Bone-Conducting Headphones(also: Bone Conduction Headphones, Bone Conduction Headset)

Headphones that transmit sound by vibrating the skull bones directly to the inner ear, bypassing the outer and middle ear and leaving the ear canals open. In accessibility contexts they are widely used by blind travellers and wayfinding systems because the wearer can continue to…