Glossary

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Accessibility API(also: Accessibility Application Programming Interface, A11y API)

A set of programming interfaces provided by operating systems that allow assistive technologies and accessibility services to interact with application user interfaces. Accessibility APIs expose information about on-screen elements — their labels, roles, states, and…

Accessibility Crawler(also: automated accessibility crawler, app crawler for accessibility)

An automated tool that systematically explores an application's user interface—by simulating taps, swipes, and navigation—to discover screens and UI components and then evaluate each against accessibility rules without human involvement. On Android, crawlers typically drive the…

Accessibility Feature Discovery(also: Feature Discoverability, Accessibility Awareness)

The process by which users learn about, find, and activate accessibility features available on their devices or in software. Research shows that the vast majority of users — particularly older adults — are unaware of built-in accessibility features on their smartphones and…

Accessibility Focus(also: A11y Focus, Screen Reader Focus)

The currently selected element in a user interface as perceived by a screen reader or other assistive technology. When an element has accessibility focus, the screen reader announces its description and the user can interact with it. Only one element can have accessibility focus…

Accessibility Scanner(also: Google Accessibility Scanner, Android Accessibility Scanner)

A testing tool developed by Google that scans Android app screens for common accessibility issues. The scanner checks for problems such as missing content descriptions on interactive elements, insufficient touch target sizes, and low color contrast. It can be run on any Android…

Adaptive Typography(also: Context-Aware Typography, Dynamic Typography)

The practice of adjusting text presentation - font size, weight, line spacing, character spacing, contrast, and colour - automatically or semi-automatically in response to the user's current needs and context. Adaptive typography goes beyond static accessibility settings by…

Android Accessibility(also: Android A11y)

The accessibility features, APIs, and design guidelines built into the Android operating system that enable people with disabilities to use Android devices. Android accessibility includes TalkBack (screen reader), Switch Access, Voice Access, magnification, display adjustments,…

Android Accessibility Service(also: AccessibilityService, Android a11y Service)

The Android Accessibility Service is a system-level API that lets an app observe and interact with the UI of other applications on the device, exposing the hierarchical view tree (class names, text, bounds, clickability) and dispatching events such as focus changes, clicks, and…

App Review Mining(also: App Store Review Analysis, User Review Mining)

The process of systematically extracting, classifying, and analyzing user reviews from app stores such as Google Play and the Apple App Store to identify patterns, issues, and feature requests. In accessibility research, app review mining is used to discover real-world…

AssistiveTouch

An iOS accessibility feature that provides an on-screen menu of customizable touch-based shortcuts, allowing users to perform gestures and actions that might otherwise require physical buttons or complex multi-finger gestures. AssistiveTouch is particularly helpful for people…

Auto-Correction(also: Autocorrect, Automatic error correction, Spell correction)

A software feature that automatically detects and corrects typing errors, typically by comparing entered text against a dictionary and suggesting or applying the closest match based on string distance algorithms. Auto-correction is particularly important for accessible text…

BBC Mobile Accessibility Guidelines(also: BBC MAG)

A comprehensive set of accessibility standards developed by the BBC for mobile application and web content design. The guidelines cover areas including design, editorial, code, and testing, with specific recommendations for touch targets, text sizing, color contrast, and…

Back Tap(also: Back Tap Gesture)

An iOS accessibility feature that allows users to trigger actions by tapping on the back of their iPhone two or three times. Back Tap can be configured to activate shortcuts, accessibility features, or system functions without requiring precise touchscreen interaction. For…

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 Authentication(also: Biometrics, Biometric Security, Behavioral Biometrics)

Security technology that uses unique biological or behavioral characteristics to verify identity, including fingerprints, facial recognition, iris scans, voice patterns, and handwritten signatures. Accessibility considerations are critical because many biometric systems assume…

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.…

Braille Input(also: Braille Keyboard Input, Braille Screen Input)

A text entry method that allows users to type characters using Braille code on a device, rather than a standard QWERTY keyboard. On touchscreen devices, Braille input typically maps finger taps or gestures to the six dots of a Braille cell, enabling blind users who know Braille…

Braille Screen Input(also: BSI)

A built-in iOS accessibility feature that turns the touchscreen of an iPhone or iPad into a virtual Braille keyboard. When activated through VoiceOver, users can type Braille characters by tapping the screen with multiple fingers simultaneously, mimicking the six-key layout of a…

Camera Aiming(also: Camera Pointing, Camera Guidance)

The challenge blind users face in correctly positioning and aiming a camera to capture the intended visual content. Since blind users cannot see the camera viewfinder, they may inadvertently capture too much, too little, or entirely unintended content, contributing to privacy…

Camera Phone(also: Smartphone Camera, Mobile Camera)

A camera phone is a mobile phone equipped with a built-in image sensor, which in an accessibility context serves as the input device for a wide class of vision-based assistive applications. Modern smartphone cameras enable live scene description (Seeing AI, Be My AI), object…

Click-on-Lift(also: Lift-off Activation, Release Activation)

An interaction technique where a touch target is activated only when the user lifts their finger from the screen while still within the target area, rather than registering the action at the point of initial contact. This approach is particularly beneficial for users with hand…

Content Description(also: contentDescription, Android Content Description)

A text attribute on Android UI elements that provides an accessible label for screen readers like TalkBack. Content descriptions serve the same purpose as alt text on web images — they convey the meaning or function of visual elements to users who cannot see them. For…

Continuous Motion Input(also: Gesture Typing, Swipe Input)

A text entry method where the user traces a continuous path across an on-screen keyboard, passing through the desired letters or keys without lifting their finger. This approach can be faster than discrete tapping and is particularly beneficial for users with motor impairments…

Cross-Platform Development(also: Cross-Platform Framework, Multi-Platform Development)

A software development approach that allows a single codebase to run on multiple operating systems or device platforms, such as iOS and Android. Frameworks like React Native, Flutter, and Xamarin enable developers to write code once and deploy it across platforms, reducing…

Cross-Platform Development Framework(also: CPDF, Cross-Platform Framework)

A software development toolkit that allows developers to write application code once and deploy it on multiple operating systems, such as iOS and Android. Popular examples include React Native, Xamarin, and Flutter. While CPDFs reduce development and maintenance costs, research…

Dark Mode(also: Dark Theme, Night Mode)

A display setting that uses light-colored text and interface elements on a dark background, reversing the typical light-mode color scheme. Dark mode can benefit users with light sensitivity, photophobia, or certain visual conditions by reducing screen glare and brightness.…

Default Delivery Context(also: DDC)

A baseline set of device capabilities defined by the W3C Mobile Web Best Practices specification, used as a reference point for evaluating mobile web content. The Default Delivery Context specifies minimum characteristics such as a 120-pixel screen width, XHTML Basic 1.1…

Delivery Context

Delivery context is a term defined by the W3C Device Independence Working Group to describe the set of attributes that characterize the environment in which web content is delivered and consumed. This includes device capabilities (screen size, supported markup languages, color…

Device Switching(also: Device Transition, Cross-Device Interaction)

The process of moving between different computing devices to complete tasks, such as switching from a smartphone to a laptop or tablet. For people with motor impairments, particularly wheelchair users, device switching presents significant accessibility barriers because it often…

Digital Financial Inclusion(also: Financial Technology Accessibility, Inclusive Fintech)

Ensuring that digital financial services — including mobile banking, mobile money (like M-Pesa), online payments, and digital wallets — are accessible to and usable by people with disabilities. Digital financial inclusion is a critical accessibility issue because financial…

Disambiguation(also: Target Disambiguation, Touch Disambiguation)

In accessible interface design, disambiguation is the process of resolving ambiguity when a user's input could correspond to more than one interactive target. This commonly occurs on touchscreens where small, densely packed elements make precise selection difficult, particularly…

Dynamic Type(also: Dynamic Text Size, Text Scaling, Font Scaling)

An iOS accessibility feature that allows users to adjust the system-wide text size to meet their reading needs, from very small to very large. Apps that support Dynamic Type automatically reflow and resize their text content when the user changes their preferred text size in…

Enhanced Area Touch(also: Area Touch, Expanded Touch Area)

A touchscreen interaction technique that enlarges the effective touch point from a single pixel to a larger circular area, expanding both the motor space (the physical area the user needs to target) and the visual space (the on-screen representation of targets). When multiple…

Error correction strategy(also: Text correction, Input error recovery)

The methods and behaviours users employ to detect and fix errors during text input, including backspace deletion, cursor repositioning, autocorrect, and retyping. For blind and visually impaired users, error correction is disproportionately costly because detecting errors…

Explore by Touch(also: Touch Exploration)

A screen reader interaction mode on touchscreen devices in which users drag their finger across the screen to discover and hear descriptions of interface elements beneath their fingertip. When Explore by Touch is active, a single tap does not activate a control — instead, the…

Eyes-free Interaction(also: Eyes-free Input, Nonvisual Interaction, Eyes-free Interface)

Interaction techniques that allow users to operate devices without looking at the screen or interface. Eyes-free interaction is essential for people who are blind, but also benefits sighted users in contexts where visual attention is unavailable or dangerous, such as while…

Fat Finger Problem(also: Fat Finger Effect, Finger Occlusion)

A fundamental challenge in touchscreen interaction where the user's finger is larger than the target being selected, causing difficulty in precise target acquisition. The finger both occludes (blocks the view of) the target during selection and creates ambiguity about the exact…

Find My Things(also: FMT)

A Microsoft-developed smartphone app that lets people who are blind or have low vision train a personalized object recognizer by recording short example videos of their own items, then use the trained model to locate those items later via audio and haptic guidance. Find My…

Fintech(also: Financial Technology)

An umbrella term for software and digital-service innovations in the financial sector, including online and mobile banking, payments (e.g., Apple Pay, PayPal), budgeting apps, investment platforms, digital wallets, cryptocurrency services, and Buy-Now-Pay-Later products. Fintech…

Floating Action Button(also: FAB)

A circular button that floats above the user interface in Android apps, typically representing the primary action on a screen. Defined by Google's Material Design guidelines, FABs usually display a simple icon (such as a plus sign, pencil, or heart) without visible text labels.…

Focusable Element(also: Keyboard Focusable, Focus Target)

A GUI element that can receive input focus, allowing users to interact with it via keyboard, switch device, or assistive technology. For screen reader users navigating mobile apps, an element without focus enabled is essentially invisible—they cannot select, activate, or even…

Form Factor(also: Device Form Factor, Handset Form Factor)

Form factor refers to the overall physical size, shape, weight, and mechanical configuration of a device — for mobile phones this includes distinctions like candy-bar, clamshell (flip), slide-out keyboard, foldable, and modern all-touch slab. Form factor has direct accessibility…

Functiona11ity Error(also: Functionality Error, Functiona11ity)

A term coined by Zhong et al. (2026) — a portmanteau of 'functionality' and 'a11y' (accessibility) — for an accessibility barrier that only manifests through interaction. The static state of the UI appears accessible (elements have labels, sufficient contrast, correct roles),…

GUI Widget(also: UI Widget, User Interface Widget, Control)

A graphical user interface element that users can interact with or that displays information, such as buttons, text fields, images, checkboxes, and sliders. In mobile accessibility, widget types determine which accessibility requirements apply—interactive widgets like buttons…

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…

Gesture Typing(also: Swipe Typing, Trace Typing, Glide Typing)

A text entry method on touchscreen devices where the user enters a word by continuously gliding their finger from letter to letter on a virtual keyboard without lifting it, rather than tapping each key individually. The continuous trace is interpreted by a statistical decoder…

Gesture sonification(also: Touch sonification, Gesture-to-sound mapping)

The technique of converting touchscreen finger movements into real-time audio representations by mapping spatial position to sound parameters — typically pitch for vertical position and stereo panning for horizontal position. Gesture sonification enables blind and visually…

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 Input(also: Gesture input, Gestural input, Gesture-based text entry)

An input method that interprets finger or hand movements — such as swipes, taps, and drawn paths — as commands or text characters. For people with visual impairments, gesture-based input on touchscreens offers an alternative to traditional keyboard layouts that require targeting…

Home Button(also: Home Key, Home Screen Button)

The home button is a persistent, consistently-placed control on a device that returns the user to a known starting state — typically the home screen or main menu — from anywhere in the interface. From an accessibility standpoint, the value of a reliable home button is cognitive:…