Glossary
Searchable terminology from accessibility, web standards, and related fields.
78 results found in Visual Accessibility.
- Colours of Confusion (Confusion Colors, Confusable Colours, Metameric Pairs)
- Pairs or sets of colours that appear distinct to people with typical colour vision but appear identical or nearly identical to people with a specific type of colour vision deficiency. These colour pai…
- Comic Strip Conversations (CSC)
- A visual-support technique developed by Carol Gray (1994) for autistic children and adolescents, in which a social interaction is illustrated as a short comic strip with simple stick figures, speech b…
- Conditional Formatting
- Conditional formatting is a spreadsheet feature that automatically applies visual styles — fill color, font color, bold text, icons, data bars — to cells whose values meet specified rules (for example…
- Contrast Ratio (Color Contrast Ratio, Luminance Contrast Ratio)
- A numerical measure of the difference in perceived brightness between two colors, expressed as a ratio ranging from 1:1 (no contrast) to 21:1 (maximum contrast, black on white). WCAG 2.2 requires a mi…
- Cursor Locator (Pointer Locator, Cursor Finder, Find My Cursor)
- A software utility that helps users find the position of their mouse pointer on screen when it has been lost from view. Cursor locators typically activate through a keyboard shortcut or by detecting p…
- Dark Mode (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, photophob…
- Data Visualization (Data Viz, Information Visualization)
- The graphical representation of data and information using visual elements such as charts, graphs, maps, and diagrams. While data visualization is a powerful tool for communicating patterns and insigh…
- Deuteranomaly (Deutan Anomalous Trichromacy)
- The most common type of colour vision deficiency, where the medium-wavelength (green) cone cells have a shifted sensitivity range. Deuteranomaly is a milder form of deutan CVD compared to deuteranopia…
- Deuteranopia (Deutan Dichromacy, Green-Blind)
- A type of colour vision deficiency caused by the complete absence of medium-wavelength (green) cone cells in the retina. Deuteranopia is the most common form of dichromacy, causing difficulty distingu…
- Dichromacy (Dichromatic Vision)
- A category of colour vision deficiency in which one of the three types of cone cells is completely absent, reducing colour perception to two primary channels instead of three. The three forms are prot…
- Discrimination Ellipse (Discrimination Ellipsoid, MacAdam Ellipse)
- A region in a color space surrounding a given color within which other colors cannot be distinguished from it by an observer. In two dimensions this region forms an ellipse; in three-dimensional color…
- Dynamic Type (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 r…
- Font Accessibility (Accessible Fonts, Dyslexia-Friendly Fonts)
- The selection and design of typefaces to maximize readability for people with disabilities, particularly dyslexia and low vision. Research has evaluated various font properties for accessibility, find…
- Graph Accessibility (Chart Accessibility, Data Visualization Accessibility)
- The practice of making charts, graphs, and other data visualisations perceivable and understandable to people with disabilities, particularly those who are blind or have low vision. Graph accessibilit…
- Haptic Graph (Haptic Chart, Force-feedback Graph)
- A haptic graph is a non-visual rendering of a chart or graph — a bar chart, line graph, scatter plot, or mathematical function — that a blind or low-vision user explores by touch, typically through a …
- High Contrast Mode (High Contrast, High Contrast Display)
- An operating system or browser display setting that increases the visual distinction between foreground and background elements by using a limited colour palette with strongly contrasting colours, typ…
- Icon Size (Target Size, Touch Target Size)
- The physical or rendered dimensions of graphical interface elements such as icons, buttons, and interactive controls. Research consistently shows that larger icon sizes improve interaction performance…
- Image Accessibility (Visual Content Accessibility)
- The practice of making images perceivable and understandable to people who cannot see them, primarily through alternative text descriptions. Image accessibility is a foundational requirement of WCAG (…
- Image Description App (Visual assistance app, AI visual description app)
- A smartphone or wearable application that captures an image of the user's surroundings and returns a spoken or textual description of its content, aimed primarily at blind and low-vision users. Early …
- Luminance Contrast (Brightness Contrast)
- The difference in perceived brightness between two adjacent surfaces or objects, as opposed to color contrast which involves differences in hue. Luminance contrast is particularly important for people…