Glossary
Searchable terminology from accessibility, web standards, and related fields.
6660 terms — page 332 of 333
- YOLO (You Only Look Once)
- YOLO (You Only Look Once) is a real-time object detection algorithm that identifies and locates objects within images or video frames in a single pass through a neural network. In accessibility applic…
- YOLO (You Only Look Once) (YOLO, YOLOv8, YOLO Object Detector)
- A family of real-time object detection neural networks that predict bounding boxes and class labels in a single forward pass over an image, rather than using a two-stage propose-then-classify pipeline…
- YouDescribe
- A free web platform operated by the Smith-Kettlewell Eye Research Institute that enables volunteers to crowdsource audio descriptions for YouTube videos. Viewers can request a video be described and s…
- YouTube Accessibility (Video Platform Accessibility)
- The degree to which YouTube and similar video platforms can be effectively used by people with disabilities, including availability of captions, audio descriptions, screen reader compatibility, and ke…
- Z-Order (Stacking Order, Layer Order)
- Z-order refers to the front-to-back layering sequence of overlapping objects on a 2-D digital canvas, determining which objects appear in front of or behind others. In accessibility, Z-order is signif…
- Zancolli Classification (Zancolli Scale)
- A clinical classification system for residual upper-limb function after cervical spinal cord injury, developed by Argentine surgeon Eduardo Zancolli. The scale categorises hand and wrist function by t…
- Zeigarnik Effect
- A psychological phenomenon identified by Bluma Zeigarnik in 1927 describing the tendency for people to remember interrupted or incomplete tasks better than completed ones. The effect explains why part…
- Zernike Polynomials (Zernike Coefficients, Zernike Modes)
- A set of mathematical functions used to describe the shape of optical wavefronts, commonly employed in ophthalmology and optometry to characterise the optical aberrations of the human eye. Each Zernik…
- Zero-Knowledge Proof (ZKP, Zero-Knowledge Protocol)
- A zero-knowledge proof (ZKP) is a cryptographic method by which one party (the prover) can convince another party (the verifier) that a statement is true without revealing any information beyond the t…
- Zero-Shot Learning (Zero-Shot Prompting, Zero-Shot Inference)
- A machine-learning approach in which a model performs a task on classes or scenarios it has never seen explicit training examples for, relying entirely on its pre-trained knowledge and the structure o…
- Zero-Touch Interaction (Touchless Interaction, Hands-Free Interaction)
- An interaction paradigm that allows users to control devices or systems without physically touching them, typically through voice commands, gestures detected by cameras or sensors, or ambient sensing.…
- ZigBee (IEEE 802.15.4)
- A low-power, low-data-rate wireless networking protocol based on the IEEE 802.15.4 standard, designed for short-range communication between devices in personal area networks. In accessibility and assi…
- Zipf's Law
- A statistical observation that in any natural language corpus, the frequency of a word is inversely proportional to its rank in the frequency table. The most common word occurs roughly twice as often …
- Zone of Proximal Development (ZPD)
- A concept from educational psychologist Lev Vygotsky describing the range of tasks that a learner can perform with the assistance of a more competent individual (scaffolding) but cannot yet perform in…
- Zoom Fatigue (Video Call Fatigue, Teleconference Fatigue)
- The exhaustion and mental strain experienced from prolonged use of video conferencing platforms, caused by the increased cognitive effort required to process non-verbal cues such as facial expressions…
- Zoom Interface (Zoom Screen, Zoomable User Interface, ZUI)
- A user interface technique that allows users to magnify a portion of the screen to increase the effective size of interface elements, making them easier to select with low-precision pointing devices s…
- Zoom cycling (Zoom toggling, Magnification cycling)
- An interaction behaviour observed in screen magnifier users who frequently alternate between high magnification (to read fine details like axis labels and segment boundaries) and lower magnification (…
- ZoomText
- A commercial screen magnification and screen reading software for Windows, developed by Freedom Scientific (formerly Ai Squared). ZoomText provides up to 60x magnification along with features like smo…
- aDesigner
- aDesigner is an accessibility evaluation tool for web designers, originally released by IBM in the mid-2000s. It combined automated WCAG checking with simulations of low vision (contrast loss, blur, c…
- axe DevTools (axe, axe-core)
- A widely used suite of automated accessibility testing tools developed by Deque Systems, available as browser extensions, command-line tools, and integrable libraries. The axe-core engine is an open-s…