Glossary of Web Accessibility
It’s helpful to understand some of the common words used in discussions about web accessibility and ADA compliance. Some words and acronyms may seem like a foreign language.
To make sense of it, here is a glossary of web accessibility terms.
508 (Section 508)
Section 508 of the Rehabilitation Act was enacted to eliminate barriers in information technology, to make available new opportunities for people with disabilities, and to encourage the development of technologies that will help achieve these goals. Under Section 508 (29 U.S.C. § 794d), Federal Agencies must give disabled employees and members of the public access to information that is comparable to the access available to others.
The measure of a web page’s usability by persons with one or more disabilities.
Shorthand for “accessibility.” It is an A followed by 11 letters and ending in Y.
Short text in the HTML code used to describe images—usually 125 characters or less.
Alternative Equivalents for Content
Content that fulfills the same function for a person with a disability as it does for a person without a disability.
Technologies (software or hardware) that increase, maintain or improve the functional capabilities of individuals with disabilities when interacting with computers or computer-based systems.
Web browsers that provide a text-to-speech capability for the blind and visually impaired.
Machines that convert text on a screen to braille by raising bumps through holes on a flat surface.
A visual indication that a given word or item on a Web page is clickable. Cues that can be used to indicate the clickability of an item include color, underlining, bullets, and arrows.
Takes the spoken content in video and audio files and present them as text. Search engines can’t watch a video or listen to an audio file, but they do index text. It may be called a transcript.
Contrast is the perceived difference between two adjacent colors. People with color blindness or visual impairment may not perceive text elements with low color contrast.
The organization of web pages through headings (H1, H2, H3, etc) that help users get a sense of the page’s organization and structure. It benefits screen readers and individuals with cognitive disabilities.
Short for Hypertext Markup Language, a standardized system for tagging text files to achieve font, color, graphic, and hyperlink effects on World Wide Web pages
It is a bulleted outline text version of the site navigation. The anchor text displayed in the outline is linked to the page it references. It helps users easily navigate a website.
The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) recognizes the W3C WCAG 2.0 and WCAG 2.1 standards, referred to as ISO/IEC 40500 for short.
Luminance contrast ratio
A measure of the difference between foreground and background; specific minimal values are recommended via WCAG 2.0.
Non-text content includes images, text in raster images, animations (e.g., animated GIFs), applets and programmatic objects, ascii art, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video. Screen readers may not be able to interpret this information.
Where the computer’s focus is on a Web page.
A software program used to allow reading of content and navigation of the screen using speech or Braille output. Used primarily by people who have difficulty seeing. JAWS and NVDA are examples.
Provides a systematic and sequential way for people who cannot use a mouse, to use the computer keyboard tab key to rapidly scan through links, headers, list items, or other structural items on a Web page. People using screen readers — whether because they are blind or dyslexic — may tab through items on a page, as well as people using voice recognition.
A section of the ADA that prohibits disability-based discrimination on the part of state and local governments.
A section of the ADA that prohibits disability-based discrimination for “places of public accommodations”: private businesses that are open to the public, such as restaurants, hotels, movie theaters, museums, and doctor’s offices. It is generally considered to apply to web sites, but the issue is the focus of the growing number of lawsuits.
The descriptive tags that appear at the top of your browser and in search engine results pages that tell those searching exactly what they can expect from your page.
A text-only version of what’s said in video or audio; they are not real time and they generally are limited to speech only; they are not a recommended substitute for captions.
Where the user’s focus is on a Web page; generally represented by a dashed box that appears around items on the page and associated with tabbing.
The World Wide Web Consortium is an international community where Member organizations, a full-time staff, and the public work together to develop Web standards.
The Web Content Accessibility Guidelines (WCAG) 2.0 is focused on providing an international technical standard for web content. It has 12 guidelines that are organized under four principles: perceivable, operable, understandable, and robust. The guidelines each have testable success criteria outlined in three levels: A, AA, and AAA.
Provides 17 additional success criteria to WCAG 2.0 to address: mobile accessibility, people with low vision, and people with cognitive and learning disabilities.
The Web Accessibility Initiative is an effort by the WC3 to improve the accessibility of the World Wide Web for people with disabilities.
The design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design.
Read more about web accessibility and compliance.