Glossary

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Self-localization(also: Indoor Localization, Position Estimation)

The process by which a system or device determines its own position within an environment, typically using a combination of sensors, maps, and reference points. In assistive technology for blind and visually impaired users, self-localization is a critical component of indoor…

Self-presentation(also: Impression management, Identity management)

The process by which individuals control how they are perceived by others, selecting which aspects of their identity to reveal, emphasise, or conceal in different social contexts. For people with invisible disabilities, self-presentation involves ongoing decisions about whether…

Self-tracking(also: Quantified Self, Self-monitoring, Personal Informatics)

The practice of using technology — typically wearable devices like smartwatches and fitness trackers — to systematically record and monitor personal data about one's own behaviour, health, or activities. Self-tracking can help individuals, including older adults and people with…

Semantic Abstraction

The practice of defining interface elements, content, or interactions by their meaning and purpose rather than their specific visual or physical presentation. In accessibility, semantic abstraction is a foundational principle — semantic HTML elements like nav, main, and button…

Semantic Accessibility

An approach to web accessibility that focuses on the predictability and consistency of user interface behavior, layout, and interaction patterns rather than the underlying code. Semantic accessibility ensures that similar elements appear in the same locations across pages, menus…

Semantic Accessibility Violation(also: Semantic A11y Violation)

An accessibility issue where HTML elements or attributes are technically present but fail to convey meaningful information to users with disabilities. Examples include alt text set to generic values like "image" instead of describing actual content, button labels that do not…

Semantic Analysis(also: Semantic Content Analysis, Semantic Similarity)

The computational process of determining meaning and relationships within text, images, or other content by analyzing their semantic properties rather than just surface-level features. In accessibility, semantic analysis enables automated tools to go beyond detecting the…

Semantic Annotation(also: Semantic Markup, Semantic Tagging)

The process of adding machine-readable metadata to web content that describes the meaning of the content rather than its visual presentation. Unlike HTML markup which primarily specifies how content should be displayed (font size, color, layout), semantic annotations describe…

Semantic Bookmarking(also: Semantic Bookmark, Concept-Based Bookmarking)

A web navigation technique that associates saved page locations with meaningful conceptual labels from a domain ontology rather than with specific structural positions in the HTML code. Unlike traditional bookmarks that reference a URL or a position in the document's DOM tree…

Semantic Compaction(also: Minspeak)

A method of encoding language for augmentative and alternative communication (AAC) that maps concepts onto sequences of multi-meaning icons. Each icon is deliberately ambiguous, and meaning is resolved when icons are combined into sequences called iconic sentences. For example,…

Semantic Data Extraction(also: Structured Data Extraction, Information Extraction)

The process of extracting structured, meaningful data from unstructured or semi-structured sources such as images, documents, web pages, or natural language text, preserving the semantic relationships between data elements. In accessibility, semantic data extraction is used to…

Semantic Description(also: SD, Navigational Semantic Description)

A formal representation of the meaningful structure and navigational relationships within a complex document component such as an HTML table, frame, or XML fragment. Semantic descriptions capture what groups of content mean and how they relate to each other, going beyond…

Semantic Disambiguation(also: Word Sense Disambiguation)

Semantic disambiguation is the process of determining the intended meaning of a word, symbol, or input when multiple interpretations are possible. In accessibility and assistive technology contexts, semantic disambiguation is important in communication aids, predictive text…

Semantic Enrichment(also: Semantic Annotation, Semantic Markup Enhancement)

Semantic enrichment is the process of adding meaningful structural and contextual information to content that may lack it in its original representation. In the context of web accessibility, this often involves augmenting presentation-oriented markup with data attributes or…

Semantic Grounding(also: Meaning Grounding, Form-Meaning Mapping)

A design principle in which practice or interaction is accompanied by explanations that connect the form of an action to its underlying meaning, rather than treating the action as an arbitrary symbol to memorise. In sign language learning, semantic grounding pairs a sign with…

Semantic HTML

The practice of using HTML elements according to their intended meaning rather than their visual appearance. Semantic elements like <nav>, <main>, <article>, <aside>, and <header> communicate the structure and purpose of content to browsers, assistive technologies, and search…

Semantic Hearing(also: Programmable Hearing, Intent-Aware Hearing)

A research paradigm and class of systems that treat the user's auditory environment as something programmable: rather than uniformly amplifying or suppressing all sound, the wearable headphone or earbud uses on-device machine learning to selectively extract or attenuate specific…

Semantic Hierarchy(also: Semantic Tree, Component Hierarchy)

A structured, tree-based representation of a complex object that organizes its components by meaning and relationship rather than by raw data. In accessible 3-D modeling, a semantic hierarchy breaks down a model into named, meaningful parts (e.g., "snowman body" containing…

Semantic Level(also: Semantic Content Level, Alt Text Semantic Level)

A framework for categorizing the depth of information conveyed in alt text descriptions of data visualizations, introduced by Lundgard and Satyanarayan. The four levels are: Level 1 (construction details such as chart type, axes, and encodings), Level 2 (statistical properties…

Semantic Listening

A mode of listening, identified by composer and theorist Pierre Schaeffer, in which the listener focuses on decoding a coded audio signal to arrive at its intended message — for example, understanding a musical motif as representing a particular region or culture. Semantic…

Semantic Model(also: Semantic Tree, Semantic Web Model)

An abstract representation of a web page that captures the meaning and relationships of its content, rather than its raw HTML structure. Unlike the Document Object Model (DOM), which represents syntactic elements, a semantic model groups related elements into meaningful entities…

Semantic Navigation(also: Semantic Navigation Framework, Structured Navigation)

An approach to organizing digital content into a meaningful hierarchical structure that users can navigate through logically ordered elements rather than by spatial position. In the context of accessible data visualizations, semantic navigation frameworks arrange chart…

Semantic Network(also: Semantic Web, Associative Network)

A knowledge representation structure in which concepts are represented as nodes and the relationships between them as links or edges. In accessibility and AAC contexts, semantic networks model how words and concepts are associated in the human mind, enabling vocabulary tools to…

Semantic Partitioning(also: Web Page Partitioning, Content Partitioning)

A technique for automatically dividing a web page into semantically meaningful segments or blocks based on the structural and visual properties of its HTML content. Semantic partitioning analyzes the DOM tree to group related elements using spatial locality (items close together…

Semantic Redundancy(also: Redundant Multimodal Input)

A design strategy in multimodal interfaces where the same command or message is conveyed simultaneously through multiple input channels, each independently signalling the user's intent. For example, a user might perform a head nod and a hand gesture at the same time, both…

Semantic Relatedness(also: Semantic Similarity, Semantic Association)

A measure of how closely related two words or concepts are in meaning, encompassing various types of relationships including synonymy, hyponymy, meronymy, and general topical association. In assistive technology, semantic relatedness is used to improve word prediction and…

Semantic Scene Graph(also: SSG, scene graph)

A semantic scene graph is a structured data representation of a 3D or 2D environment that encodes objects, their properties (such as position, size, color, and audio characteristics), and the spatial and hierarchical relationships between them. In accessibility research,…

Semantic Segmentation(also: Pixel-Level Classification, Scene Parsing)

A computer vision technique that classifies every pixel in an image into a predefined category, producing a detailed map of what objects are present and where they are located. Unlike object detection (which draws bounding boxes around objects), semantic segmentation provides…

Semantic Structure(also: Semantic Representation)

Semantic structure refers to the meaningful organisation of content that captures the conceptual relationships between pieces of information, as distinct from the syntactic or visual presentation of that content. In web accessibility, semantic structure is critical because…

Semantic Tagging(also: Structural Tagging, PDF Semantic Markup)

The process of marking up content within a PDF document with tags that convey the semantic meaning and structural role of each element — such as headings, paragraphs, lists, tables, figures, and links — rather than just visual formatting. Proper semantic tagging ensures that…

Semantic Taxonomy(also: Environmental Semantic Taxonomy)

A structured classification system that organizes and labels environmental features and attributes using standardized vocabulary, enabling consistent description and retrieval of information about physical spaces. In accessible navigation, semantic taxonomies define the…

Semantic Transcoding(also: Annotation-driven Transcoding, Ontology-based Transcoding)

Semantic transcoding is the transformation of web content using explicit semantic information about the structure, role, or meaning of page elements — typically supplied through external annotations, ontologies, microformats, or ARIA. Because the transformation uses real…

Semantic Web(also: Web of Data, Linked Data)

An extension of the World Wide Web in which information is given well-defined meaning through standardized formats and technologies (such as RDFa, OWL, and ontologies), enabling machines to interpret and process web content more intelligently. For accessibility, semantic web…

Semantic decomposition

An analysis method that models a system as a hierarchy of ontological dependencies based on meaning and conceptual relationships, rather than breaking it down by functional tasks. In user interface design, semantic decomposition contrasts with traditional task-based…

Semantic distance(also: Semantic similarity, Word embedding distance)

A computational measure of how different two words are in meaning, typically derived from word embedding models like word2vec that represent words as vectors in a high-dimensional space. In caption evaluation for DHH users, semantic distance between an ASR error and the intended…

Semantic feature(also: Environmental feature, Landmark annotation)

A meaningful environmental attribute associated with a specific location in a navigation system, such as a doorway, floor surface change, point of interest, or tactile ground indicator. In accessible indoor navigation, semantic features serve a dual purpose: confirming the…

Semantically Unpredictable Sentences(also: SUS, SUS Test)

A standardised method for evaluating speech intelligibility in which listeners are presented with sentences that are grammatically correct but semantically meaningless, such as "A polite art jumps beneath the arms" or "The law that finished shows the boots." Because the…

Semi-Automatic Evaluation(also: Semi-Automated Testing, Guided Manual Evaluation)

An approach to accessibility evaluation that combines automated checks with human expert judgment. Semi-automatic tools run algorithmic tests to detect issues that can be identified programmatically — such as missing alt text or invalid ARIA attributes — and then guide the…

Semi-Automatic Wizard-of-Oz(also: Semi-Automatic WoZ)

A hybrid Wizard-of-Oz study methodology in which part of a prototype system is implemented with real automation while a human researcher (the 'wizard') intervenes only for components that are not yet reliable enough to run autonomously. For example, an AI agent may generate…

Semi-structured Interview(also: Semi-structured Interviewing)

A semi-structured interview is a qualitative research method in which the interviewer works from a guide of open-ended topics or questions but adapts the order, wording, and depth of probing to the flow of each conversation. It sits between a rigid structured interview (fixed…

Semiotic Engineering(also: Semiotics of HCI)

A theoretical framework developed by Clarisse Siqueira de Souza that views human-computer interaction as a form of designer-to-user communication mediated by the interface. In this model, the interface is not merely a tool but a message from designers to users, carrying an…

Semiotic Inspection Method(also: SIM, MIS)

An evaluation method from Semiotic Engineering theory that systematically assesses the communicability of an interactive system by examining how well the designer's intended message is conveyed through the interface. The evaluator analyzes three types of interface signs…

Sense of Agency(also: User Agency, Personal Agency)

The subjective experience of being in control of one's own actions and their effects on the external world. In accessible design, supporting sense of agency means ensuring users feel empowered to make choices, initiate interactions, and influence outcomes rather than being…

Sense of Control(also: Perceived control, Locus of control (task-level))

A psychological construct describing a user's subjective feeling of agency over what a system does, distinct from objective control measures such as available options or task-completion rates. In accessibility research on AI-assisted tools, sense of control has emerged as a…

Sense of Presence(also: Virtual Presence, Spatial Presence)

The subjective feeling of "being there" in a virtual environment, encompassing spatial presence (feeling physically located in the virtual space), involvement (attention directed at the virtual world), and experienced realism (how lifelike the environment feels). Sense of…

SenseCam(also: Microsoft SenseCam, Vicon Revue)

A wearable digital camera originally developed by Microsoft Research that automatically captures photos throughout the day without requiring the wearer to actively take pictures. SenseCam is worn around the neck and uses sensors (light level, temperature, passive infrared for…

Sensemaking(also: Sense-making)

The cognitive and social process of giving structure to ambiguous, incomplete, or unfamiliar information so that one can act on it. In HCI and information science, sensemaking is studied as iterative cycles of foraging for information, building mental representations, testing…

Sensitivity(also: Recall, Thoroughness, Completeness)

In the context of accessibility evaluation, sensitivity (also called recall or thoroughness) is the proportion of true accessibility problems that are successfully identified and reported by an evaluator. High sensitivity means that most real barriers are found, while low…

Sensorimotor(also: Sensorimotor System, Sensorimotor Control)

Relating to the integration of sensory input (proprioception, vision, touch) with motor output (muscle activation and coordinated movement). Sensorimotor processes let people plan, execute, and correct movements in real time, usually without conscious effort. Neurological and…

Sensorimotor Rhythm(also: SMR, Sensorimotor Cortical Rhythm)

Oscillatory electrical brain activity recorded over the sensorimotor cortex, the brain region responsible for planning and executing voluntary movements. Sensorimotor rhythms include mu rhythms (8-12 Hz) and beta rhythms (18-26 Hz), which change in amplitude when a person…