Glossary

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BATE Principle(also: Beyond Accessibility to Efficiency)

A design principle for assistive technology stating that devices should not merely provide basic access to a task but should enable a person with a disability to perform that task with the same efficiency as a non-disabled person. Coined in the iCARE Reader project at Arizona…

BETSIE(also: BBC Education Text to Speech Internet Enhancer)

BETSIE (BBC Education Text to Speech Internet Enhancer) was an early web accessibility tool developed by the BBC as a CGI Perl script that produced text-only versions of web pages optimized for users of text-to-speech systems. BETSIE handled frames by serializing them,…

BIGmack Switch(also: BIGmack, BIGmack Communicator)

A single-message assistive technology device that allows a user to press a large button to play a pre-recorded message. BIGmack Switches are widely used in special education and communication interventions for individuals with significant speech and motor disabilities, including…

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

A BLE (Bluetooth Low Energy) beacon is a small wireless transmitter that broadcasts a signal at regular intervals, which can be detected by nearby smartphones to determine a user's indoor location. In accessibility contexts, networks of BLE beacons are widely used to enable…

Background Color Music(also: BCM)

A sonification technique that maps the background colors of visually distinct content regions on a web page to recognizable melodies, allowing blind users to perceive the color-based grouping structure of a page through hearing. Each background color is assigned a unique melody…

Background Mode

A privacy technique in visual assistance technologies that obfuscates a specific private object while preserving all other elements in the image or video. For example, a user might select a pill bottle as private content, and background mode would blur or hide only the pill…

Ballot Marking Device(also: BMD, Ballot Marking System)

A ballot marking device (BMD) is an electronic system that assists voters in marking their ballot selections, typically producing a printed paper ballot as a verifiable record. Unlike direct recording electronic (DRE) voting machines that store votes digitally, BMDs produce a…

Barcode(also: Bar Code, QR Code, 1D Barcode)

A barcode is a machine-readable visual encoding of data — linear (one-dimensional, such as UPC or EAN) or matrix (two-dimensional, such as QR or DataMatrix codes). In a digital accessibility context, barcodes are commonly used as a lightweight way to attach identifying or…

Barrier Pointing(also: Edge-Based Pointing)

An interaction technique for touch screens that uses the physical edges of a device as barriers to assist with target acquisition. When a target is placed near a screen edge, users can slide their finger or stylus toward the edge, using it as a physical stop to improve selection…

Bayesian Network(also: Bayes Network, Belief Network, Probabilistic Graphical Model)

A statistical model that represents probabilistic relationships among variables using a directed graph structure. In accessibility and assistive technology applications, Bayesian networks are used for behavior recognition—inferring what action a user is performing based on…

Be My AI

An AI-powered feature within the Be My Eyes app that uses GPT-4o to provide on-demand image descriptions for blind and low vision users. Users can take a photo or upload an image and receive a detailed AI-generated description, replacing the need to connect with a sighted…

Be My Eyes

A mobile application that connects blind and low-vision users with sighted volunteers or AI-powered visual assistance for help with visual tasks. Originally launched in 2015 as a crowdsourced human-to-human video call service, Be My Eyes has since integrated AI features ("Be My…

Behavioral Intervention(also: Behavior Intervention, Applied Behavior Analysis, ABA)

A systematic approach to understanding and modifying behavior, most commonly applied to support children with autism, ADHD, and other neurodevelopmental conditions. Behavioral intervention uses evidence-based techniques including prompting, reinforcement, cueing, and feedback…

Bespoke Assistive Technology(also: Bespoke AT, Custom Assistive Technology)

Assistive technology that is designed and built from scratch to meet the unique requirements of a specific individual, as opposed to adapting or modifying existing products. Bespoke AT is distinguished from DIY assistive technology by the involvement of professional designers or…

Bespoke Design(also: Custom Design, Bespoke Assistive Technology)

The creation of individually tailored products or solutions made to meet the specific needs of a single user, as opposed to mass-produced or universally designed items. In assistive technology, bespoke design addresses the reality that every person's combination of abilities,…

Bimodal Feedback(also: Dual-Modality Feedback)

A form of interface feedback that communicates information to the user through two simultaneous sensory channels, such as auditory and haptic, visual and haptic, or auditory and visual. Bimodal feedback is significant for accessibility because it provides redundancy — if a user…

Binary Selection(also: Binary Choice, Yes/No Selection)

An interaction method where users make choices between two options at each step, progressively narrowing down to their desired selection through a series of binary decisions. Binary selection is used in some AAC systems, including Look to Speak where users look left or right to…

Binaural Beats

Binaural beats are an auditory phenomenon that occurs when two tones of slightly different frequencies are played simultaneously in separate ears through headphones, creating a perceived third tone whose frequency equals the difference between the two signals. For example, a 400…

Binaural audio(also: Binaural sound, Binaural recording, 3D audio)

An audio reproduction method that uses two channels to create a three-dimensional sound experience when listened to through headphones. Binaural recordings capture or simulate the way human ears naturally perceive sound, using differences in timing, level, and frequency between…

Bio-Electrical Signal(also: Biosignal, Bioelectrical Signal, Physiological Signal)

A bio-electrical signal is an electrical potential generated by biological processes in the human body, including muscle contractions (EMG), brain activity (EEG), eye movements (EOG), heart rhythms (ECG), and skin conductance (GSR). In assistive technology, bio-electrical…

Bio-Signal(also: Biosignal, Biological Signal)

Any measurable electrical, chemical, or mechanical signal produced by the human body that can be detected by sensors and used as input for computer systems. In assistive technology, bio-signals are used to create alternative input methods for people with severe motor impairments…

Biofeedback

A therapeutic technique in which individuals are presented with real-time measurements of their physiological variables — such as heart rate, blood oxygen saturation, muscle tension, or brain waves — to help them learn to regulate these functions. In accessibility contexts,…

Biometric Authentication(also: Biometrics, Biometric Identification)

A security method that verifies a person's identity using unique biological characteristics such as fingerprints, facial features, iris patterns, or voice. For people with vision impairments, biometric authentication — particularly fingerprint recognition — is widely preferred…

Biometric Control(also: Biometric Input, Physiological Control Interface)

The use of measurable biological signals from the human body — such as brain waves (EEG), skin conductance (galvanic skin response), muscle electrical activity (EMG), heart rate, or eye movements — as input channels for controlling computers and assistive technology devices.…

Biosensor(also: Physiological Sensor, Biometric Sensor)

A device that detects and measures biological or physiological signals from the body, such as heart rate, skin conductance, temperature, or movement. Wearable biosensors are increasingly used in accessibility applications to monitor the physiological states of individuals who…

Biosignal Interface(also: Physiological Interface, Biometric Input)

An input interface that detects and interprets biological signals from the human body — such as muscle contractions (EMG), brain electrical activity (EEG), eye movements (EOG), or galvanic skin response — to generate computer commands. Biosignal interfaces are particularly…

Bite Switch(also: Bite Button, Mouth Switch)

An assistive input device consisting of a small button held in the mouth and activated by biting down on it, used by people with severe motor impairments who cannot operate hand-held controllers or switches. Bite switches are commonly used alongside joysticks or sip-and-puff…

Bixby Vision

Bixby Vision is a visual-assistance feature in Samsung's Bixby assistant, built into Samsung Galaxy phones, that uses the device camera and AI to describe scenes, read text, identify objects and currency, translate signs, and answer questions about the live camera view. For…

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 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…

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…

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…

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-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…

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…

Bone-Conduction Headset(also: Bone-conduction headphones, Bone-conduction earphones)

A headphone that delivers sound by vibrating the bones of the skull and jaw rather than projecting air through the ear canal, leaving the wearer's ears uncovered and able to hear ambient sound. Bone-conduction headsets are widely used in blind and low-vision navigation contexts…

Bounce Keys

An operating system accessibility feature that introduces a brief delay after a key press during which the same key cannot be reactivated. This prevents bounce errors — unintentional repeated presses of the same key caused by tremor, spasm, or difficulty in cleanly releasing…

Braille(also: Braille System, Braille Code)

A tactile writing system used by people who are blind or have low vision, consisting of patterns of raised dots arranged in cells of up to six dots in a 3x2 configuration. Each cell represents a letter, number, punctuation mark, or other symbol. Developed by Louis Braille in…

Braille Cell(also: Braille Character, Six-Dot Cell)

The fundamental unit of the Braille writing system, consisting of a rectangular arrangement of up to six raised dots in a 3x2 matrix (three rows, two columns). Each dot position is numbered 1-6, with dots 1-3 in the left column (top to bottom) and dots 4-6 in the right column.…

Braille Display(also: Braille Terminal, Refreshable Braille Display)

An electromechanical device that displays braille characters using small pins that raise and lower dynamically, enabling blind users to read digital text through touch. Traditional braille displays present a single line of braille text (typically 14-80 characters) and are…