Glossary

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Structural Abstraction(also: Formula Abstraction, Expression Collapsing)

Structural abstraction is an accessibility technique that simplifies complex visual structures — particularly mathematical formulas — by initially collapsing sub-expressions into symbolic summaries and allowing users to progressively expand and explore them at their own pace.…

Structural Navigation(also: Structure-Based Navigation)

A mode of screen reader navigation that allows users to move through content based on its logical or semantic structure rather than reading linearly from beginning to end. In web content, structural navigation involves jumping between headings, landmarks, lists, and other HTML…

Structured Audio(also: Structured Digital Audio)

Structured audio refers to digital audio content that has been encoded with hierarchical markers and metadata, allowing non-sequential access to specific segments such as chapters, sections, paragraphs, and phrases. Unlike linear audio recordings (such as traditional audio…

Structured Discovery(also: Structured Discovery Learning)

A teaching approach used in vision rehabilitation where instructors refrain from hand-over-hand guidance, instead encouraging blind students to work through tasks independently and develop problem-solving skills on their own. In adaptive cooking instruction, Structured Discovery…

Structured Walkthrough(also: Guided Walkthrough, Accessibility Walkthrough)

An accessibility evaluation method in which an evaluator is guided through a systematic series of checks using predefined steps, instructions, and heuristics. Unlike a full WCAG conformance review which requires expert knowledge to interpret success criteria, a structured…

Students as Partners(also: SaP, Student Partnership)

A sector-wide approach in higher education that elevates student voice by enabling students to have a collaborative, meaningful input into their university experience through a values-led approach. In disability and accessibility contexts, Students as Partners is particularly…

Study Circle(also: Folkbildning, Learning Circle)

A democratic, non-formal adult education method originating in Nordic countries where a small group of people meet regularly to discuss and learn about a specific topic. Unlike traditional classroom instruction, study circles have no teacher—instead, a facilitator guides…

Study With Me(also: Study With Me Videos, SWM)

A genre of online video content, primarily on YouTube and Twitch, where creators film themselves studying or working, often incorporating Pomodoro-style timed sessions. Viewers watch these videos while studying to simulate the experience of body doubling—creating a sense of…

StudyStream

An online platform that provides virtual body doubling through a grid-based video interface simulating a study hall or library environment. Unlike one-on-one platforms like Focusmate, StudyStream displays multiple users simultaneously, creating moderate accountability through…

Stuttering(also: Stammering, Speech Disfluency Disorder)

A speech disorder characterized by involuntary disruptions in the flow of speech, including repetitions of sounds, syllables, or words (e.g., "w-w-water"), prolongations of sounds (e.g., "sssssnake"), and blocks where airflow is stopped and no sound is produced. Stuttering…

Stylus(also: Digital Pen, Active Pen)

A pen-shaped input device used to interact with touchscreens, tablets, and other digitizer surfaces. Unlike finger touch, styluses provide a smaller contact point for precise selection, and active styluses can detect pressure, tilt, and hover states. For accessibility, styluses…

Subitizing

The rapid, accurate perception of the number of items in a small group without counting, typically for quantities up to about four or five. Subitizing is considered a core numerical ability that contributes to number sense development. Individuals with dyscalculia often have…

Subjective Image Description(also: Subjective Visual Assessment)

An image description that involves opinion, aesthetic judgment, or interpretation rather than purely factual content. Examples include assessing whether an outfit matches, whether a room setting looks nice, or whether a photograph is aesthetically pleasing. Subjective image…

Subjective cognitive decline(also: SCD, Subjective memory complaint, SMC)

A self-perceived decline in cognitive abilities, particularly memory, that is not detectable on standard cognitive tests. Individuals with subjective cognitive decline notice changes in their thinking abilities but perform normally on clinical assessments. Research suggests SCD…

Submovement(also: Movement Component, Movement Segment)

A discrete component of a larger aimed movement, separated from other submovements by pauses or changes in velocity. According to the Optimized Submovement Model from motor performance theory, a rapid aimed movement such as moving a cursor to a target consists of an initial…

Substitution Error(also: Replacement Error, Word Substitution)

A type of text error where an incorrect word or character appears in place of the intended one. Substitution errors commonly arise from speech recognition misrecognition, autocorrect mistakes, or typing errors. Correcting substitutions requires navigating to the error, selecting…

Subtitle(also: Subtitles, Open captions (video), Movie subtitles)

On-screen text that reproduces the spoken dialogue of a video, most commonly rendered in a "movie subtitle" style (white text with a black outline, one or two lines at the bottom of the frame). Subtitles are closely related to captions but are conventionally distinguished in…

Subtitles

Text displayed on screen that represents the spoken language in audio-visual content, primarily intended for viewers who do not understand the language being spoken. While often used interchangeably with captions, subtitles and captions serve different purposes: subtitles…

Subtitles(also: Captions, Closed Captions, CC)

Text displayed on screen that represents the spoken dialogue and other relevant audio information in video content. Subtitles (called captions in North America) are essential for deaf and hard of hearing viewers but are also widely used by hearing audiences in noisy…

Subtle Interaction(also: Discreet interaction)

A design approach in which interactions with a device or digital system are intentionally minimized in visibility, amplitude, or audibility to reduce social disruption, preserve user privacy, and support use in public or semi-public contexts. Subtle interactions include…

Subvocal Input(also: Subvocal Control, Subvocalisation Input)

An input method that uses very quiet or nearly silent vocalisations — sounds produced with minimal vocal effort that are typically inaudible to nearby people. Subvocal input includes techniques such as humming, whispering, or producing sounds detectable only by bone-conduction…

Success Criteria(also: Success Criterion, SC)

The testable statements within the Web Content Accessibility Guidelines (WCAG) that define specific requirements for making web content accessible. Each success criterion is assigned a conformance level (A, AA, or AAA) indicating its priority. Success criteria are…

Sufficient Techniques(also: Sufficient Advisory Techniques)

In the WCAG framework, sufficient techniques are documented methods for meeting a specific success criterion. If a content author correctly implements a sufficient technique, it is enough to satisfy the associated requirement. Multiple sufficient techniques may exist for a…

Suitcase Robot(also: Suitcase-shaped robot, Robotic suitcase)

A class of autonomous navigation robots housed inside a rolling suitcase or carry-on-shaped enclosure, designed so that a blind or low-vision user can grip the handle and be guided to a destination while appearing to any onlooker to simply be walking with a piece of luggage. The…

Summative Evaluation(also: Summative Usability Testing, Summative Assessment)

Usability evaluation conducted on functional software or high-fidelity prototypes, typically later in the development process, to measure the effectiveness of specific design choices. Summative testing uses representative users performing representative tasks and often involves…

Suno(also: Suno AI, Suno v3.5)

A commercial generative AI platform that produces full songs — lyrics, vocals, instrumentation — from short natural-language prompts specifying genre, mood, tempo, and lyrical content. Suno is widely adopted in HCI research on music co-creation, journaling, and therapy because…

Supervector(also: GMM Supervector)

A supervector is a high-dimensional feature representation created by concatenating the mean vectors from all components of a Gaussian Mixture Model (GMM) adapted to a specific speaker or utterance. This concatenation transforms variable-length speech into a fixed-length vector…

Supplemental Security Income(also: SSI)

A U.S. federal program administered by the Social Security Administration that provides cash benefits to people with disabilities, blindness, or age-related needs who have limited income and resources. SSI enforces strict asset and income limits — historically $2,000 in…

Support Indicator(also: Agreement Indicator)

A visual or textual cue that communicates the degree of agreement across multiple AI model responses for a particular claim. Support indicators help BLV users assess claim reliability by showing how many or which models agree. Research has explored four types: source-based ("3…

Support Network(also: Support Worker, Support Person, Circle of Support)

The caregivers, family members, support workers, teachers, and peers who assist a person with a disability in daily life and in participating in research or design activities. In inclusive co-design with people with intellectual or cognitive disabilities, support networks often…

Support Vector Machine(also: SVM)

A supervised machine learning algorithm used for classification and regression tasks. SVMs work by finding the optimal hyperplane that separates data points into distinct categories in a high-dimensional feature space. In accessibility research, SVMs have been used to detect…

Support worker(also: Disability support worker, Direct support professional, DSP)

A person employed to provide direct assistance and support to people with disabilities in their daily lives. Support workers help with activities of daily living, skill development, community participation, health monitoring, and personal care. In disability community centres…

Supported Decision-Making(also: SDM)

A legal and practical alternative to guardianship in which a person with a cognitive or developmental disability retains decision-making authority over their own life while receiving support from trusted people — family, friends, advocates — who help them understand options,…

Supported Employment(also: SE)

An approach to helping people with significant disabilities find and maintain competitive employment in integrated work settings, with ongoing support as needed. Unlike sheltered workshops or segregated employment, supported employment places individuals in regular workplaces…

Supporting Individual(also: Support Person, Ally)

A person — such as a partner, family member, friend, or caregiver — who provides assistance to someone with a disability and may also seek information and support on their behalf. In online disability communities, supporting individuals often search for guidance on assistive…

Supportive Empathy

A therapeutic conversational stance in which a listener responds to another person's feelings with affirmation, validation, and gentle encouragement rather than problem-solving or interpretation. In music-therapy practice supportive empathy is often paired with a 'holding'…

Surface Dyslexia

A subtype of dyslexia characterized by difficulty with whole-word recognition and irregular word reading, often resulting in confusion with homophonic or pseudo-homophonic words (such as "weather" and "whether"). People with surface dyslexia can typically sound out words using…

Surface Electromyography(also: sEMG, Surface EMG)

A non-invasive technique for measuring the electrical activity produced by skeletal muscles, using electrodes placed on the skin over the muscle. Surface EMG is used in biomechanics, prosthetic control, rehabilitation, and — increasingly — as an input modality for accessible…

Surface Haptics(also: Surface Haptic Technology)

A branch of haptic technology that creates tactile sensations directly on a flat surface, such as a touchscreen, by modulating the friction between a fingertip and the display. Unlike conventional vibration motors that shake the entire device, surface haptics produces localised…

Surface Level Change(also: Elevation Change, Grade Change)

Any change in the height of the ground or floor surface, including stairs, curbs, ramps, steps, potholes, and raised thresholds. Surface level changes are a significant mobility challenge and safety hazard for people with low vision and other disabilities. Detecting these…

Surrogate Users(also: Proxy Users)

Individuals who stand in for actual end users during design and evaluation processes, typically used when direct user involvement is impractical, ethically problematic, or insufficient. In accessibility research, surrogate users may include actors trained to portray people with…

Surround sound(also: Multichannel audio, 5.1 audio, 7.1 audio)

An audio reproduction technique that uses multiple speaker channels arranged around the listener to create an enveloping sound field. Common configurations include 5.1 (five speakers plus a subwoofer) and 7.1 (seven speakers plus a subwoofer), where speakers are placed at…

Surveillance

The systematic, focused, and often routine observation of people, their activities, or their data for purposes of influence, management, entitlement, or control. In accessibility and HCI research, surveillance is an analytical frame used to examine how monitoring technologies —…

Surveillance technology(also: Surveillance tech, Monitoring technology)

Technologies that collect, analyse, and track data about individuals' behaviours, locations, bodies, or communications. In disability contexts, surveillance technology raises justice concerns because assistive tools (computer vision for blind users, behaviour monitoring for…

Survey Accessibility(also: Accessible Surveys, Inclusive Survey Design)

The practice of designing surveys, questionnaires, and assessment tools so they can be completed by people with diverse abilities, languages, and communication preferences. Survey accessibility encompasses providing content in multiple formats (text, audio, sign language video),…

Survey Knowledge(also: Configurational Knowledge, Map-like Knowledge)

Survey knowledge is a type of spatial understanding that provides an overview or mental map of an environment, including the relationships between landmarks, streets, and points of interest. Unlike route knowledge, which gives sequential turn-by-turn directions, survey knowledge…

Sustainable Development Goals(also: SDGs, Global Goals)

A collection of 17 interlinked global goals adopted by the United Nations in 2015 as a shared blueprint for peace and prosperity by 2030. Several SDGs are directly relevant to disability inclusion: SDG 4 (quality education), SDG 8 (decent work and economic growth, promoting…

Sustainable Mobility(also: Sustainable Transportation, Green Mobility)

Transportation systems and practices that meet current mobility needs without compromising the ability of future generations to meet theirs, emphasizing reduced environmental impact, energy efficiency, and equitable access. In accessibility contexts, sustainable mobility…

Sustained Attention(also: Vigilance, Continuous Attention)

The ability to maintain focus on a task or stimulus over an extended period of time. Sustained attention is a core executive function that can be impaired in conditions such as ADHD, traumatic brain injury, and various neurodevelopmental disorders. Designing for sustained…

Swarm robotics(also: Multi-robot systems)

A field of robotics involving the coordination of multiple simple robots that work together as a group, inspired by collective behaviours in nature such as ant colonies or bird flocking. Individual robots follow simple rules, but their collective behaviour produces complex,…