Glossary
Searchable terminology from accessibility, web standards, and related fields.
6660 terms — page 126 of 333
- Fovea (Foveal Vision, Fovea Centralis)
- The small, central area of the retina responsible for sharp, detailed vision, covering approximately 1 degree of visual angle. The fovea contains the highest density of cone photoreceptors and provide…
- Fractionation (Finger Fractionation, Finger Independence)
- The ability to move individual fingers independently of one another, a key measure of fine motor control assessed in stroke rehabilitation. After a stroke, patients often lose fractionation, meaning t…
- Fragile Learning Continuity
- A framework proposed by Bhuiyan et al. (2026) to describe how accessibility in low-resource Deaf education depends not on any single feature — visibility, sign clarity, vocabulary, or connectivity — b…
- Fragile X Syndrome (FXS, Martin-Bell Syndrome)
- A genetic condition caused by a mutation in the FMR1 gene on the X chromosome, making it the most common inherited cause of intellectual disability and the most common known single-gene cause of autis…
- Frame Rate (Frames Per Second, FPS, Frame Frequency)
- Frame rate is the number of still images (frames) displayed or captured per second in a video stream, usually measured in frames per second (fps). Common values include 24 fps (cinema), 30 fps (US bro…
- Frame differencing (Temporal differencing, Background subtraction)
- A computer vision technique that detects motion or changes in video by comparing consecutive frames pixel by pixel. In accessibility applications, frame differencing can identify instructor actions in…
- Fraudulent Participants (Impostor Participants, Fake Participants)
- Individuals who falsely claim to meet a study's eligibility criteria in order to participate in research, typically for financial compensation. In accessibility research, fraudulent participants may c…
- Free-Roam Locomotion (Room-Scale VR, Physical Locomotion)
- A VR locomotion method where the user's real-world physical movement is directly mapped to movement in the virtual environment—walking forward in the real room moves the user forward in VR. While free…
- Free-Space Haptics (Mid-Air Haptics, Contactless Haptics)
- Haptic feedback technology that applies physical forces or tactile sensations to a user without requiring contact with a mechanical device or surface. Unlike traditional haptic systems that use physic…
- Freehand Gesture Interaction (Hand Tracking Interaction, Controller-Free Interaction)
- An input method for virtual and mixed reality systems that uses camera-based hand tracking to detect and interpret natural hand movements without requiring physical controllers. Freehand gestures such…
- Freeze Frame (Video Thumbnail, ASL Freeze Frame)
- In the context of ASL video interfaces, a freeze frame is a static image captured at a recognizable moment of an ASL sign, used as a visual label or thumbnail for video content. Freeze frames allow De…
- Freezing Robot Problem (Freezing robot, Robot freezing)
- A classic failure mode of autonomous robots operating among people, first characterised by Trautman and Krause (2010), in which a robot stalls indefinitely because every candidate path is blocked by p…
- Freezing of Gait (FOG, Gait Freezing, Motor Blocks)
- A common and debilitating symptom of Parkinson's Disease in which a person suddenly and temporarily feels as though their feet are glued to the floor, despite intending to walk. Freezing episodes typi…
- French Sign Language (LSF, Langue des Signes Française)
- French Sign Language (Langue des Signes Française, or LSF) is the primary sign language used by the Deaf community in France. Legally recognized by the French Handicap Law of 2005 as having educationa…
- Frenchay Aphasia Screening Test (FAST)
- A brief, standardized assessment tool used to screen for the presence and severity of aphasia in stroke survivors and others with acquired language impairments. The FAST evaluates four language areas:…
- Frequency Selectivity (Auditory Frequency Resolution, Critical Band Selectivity)
- Frequency selectivity is the auditory system's ability to separate closely-spaced frequencies into distinct perceptual streams — the reason a typical listener can follow one voice in a crowd, hear the…
- Frequency mapping (Pitch mapping, Frequency-position mapping)
- A sonification technique that encodes spatial position or data values as changes in audio frequency (pitch), creating an intuitive correspondence between vertical position and pitch height — low posit…
- Frequency shifting (Frequency transposition, Frequency lowering, Spectral shifting)
- An audio processing technique that moves sounds from one frequency range to another, typically shifting high-frequency sounds into lower frequency ranges that a person with high-frequency hearing loss…
- Friedman Test (Friedman Rank Test)
- The Friedman test is a non-parametric statistical test used to detect differences across three or more related samples - for example, the same participants rating three interface conditions. It ranks …
- Friedreich's Ataxia (FA, FRDA)
- A progressive neuromuscular disease causing increasing ataxia (loss of voluntary coordination of muscle movements), dysarthria (slurred speech), muscle weakness, and in many cases pathological nystagm…