Glossary of Accessibility Terms

If you are new to accessibility you may have noticed there are many acronyms, technical terms and other information directly related to accessibility, disabilities, and advocacy. We have developed this glossary to assist in the demystifying of these terms.

The right or opportunity to use or benefit from something. In education, this often refers to the ways in which educational institutions and public policies ensure that learners have equal access to educational opportunities and learning resources.
Access Barrier
An impediment to a learner’s access to full and equitable participation.
Properties that allow a product, service, or facility to be used by people with a wide range of capabilities, either directly or in conjunction with assistive technologies. Although the term "accessibility" typically addresses users who have a disability, the concept is not limited to disability issues. Informally, the word Accessibility is sometimes shortened to “A11y,” simply the first and last letter of “accessibility,” and the amount of letters (11) between them.
To be able to reach or use something, regardless of ability.
Accessible Content
Web site or web application content that is developed in a way to include additional structure or information that is used by assistive technology to improve the access to and consumption of the content for people with disabilities.
Accessible Media Player
Accessible media players provide a user interface that works without a mouse, through speech interface, when the page is zoomed larger, and with screen readers. For example, media players need to:
  • Provide keyboard support
  • Make the keyboard focus indicator visible
  • Provide clear labels
  • Have sufficient contrast between colors for text, controls, and backgrounds
Some media players provide additional accessibility functionality to users such as:
  • Changing the speed of the video
  • Setting how captions are displayed (e.g., text style, text size, colors, and position of the captions)
  • Reading the captions with a screen reader and braille device
  • Interactive transcripts
(SC 1.2.2)
Accessible Portable Item Protocol (APIP)
Provides assessment programs and question item developers with a data model for standardizing the interchange file format for digital test items. The APIP standard accomplishes two important goals. First, the standard allows digital tests and items to be ported across APIP-compliant test item banks. Second, it provides a test delivery interface with some information and resources required to make a test and an item accessible for many students with a variety of disabilities and special needs.
An accommodation is a means or method outside of Section 508 standards designed to assist users with disabilities in cases where the application of current Section 508 standards is neither feasible nor helpful.
Alternative Text (often referred to as “alt-text”)
Text that is added to non-text content (via HTML markup), usually images, which can be read by screen readers and other text-to-speech programs so that visually impaired or blind users are able to understand the purpose and function of the non-text content. (S.C. 1.4.5)
Assistive Technology
Any kind of tool, equipment, or product that can help a person with a disability to function successfully at school, home, work, and in the community. For example, computer software and hardware, such as voice recognition programs, screen readers, and screen magnifiers, help people with mobility and sensory impairments use computer technology. People with physical disabilities that affect movement can use wheelchairs, scooters, walkers, canes, crutches, prosthetic devices, and orthotic devices to enhance their mobility. Adaptive switches make it possible for a child with limited motor skills to play with toys and games. (SC 1.3.1)
Audio Description (AD)
An additional audio track in videos, animations, movies, tv shows, and live performances that describes visual detail on screen that’s not apparent from the audio alone, so that visually-impaired/blind users are able to understand all the content. (SC 1.2.3 & SC 1.2.5)
Braille is not a language. Rather, it is a code by which text may be written and read. Braille is a system of raised dots that can be read with the fingers by people who are blind or who have low vision, and provides a means of literacy for all.
Text-based alternatives of the audio content in a video/animation provided to convey the auditory information to users who are deaf or hard of hearing. Note: Although sometimes seemingly the same, captions and subtitles are different. Captions provide a textual copy of the audio information, whereas subtitles provide a translation of the audio to different languages. (SC 1.2.2)
Closed Captioning (CC)
Captions that can be turned on or off by the user. Closed captions can be toggled on/off, whereas open captions are always on.
Cognitive Disability
Persons with cognitive disabilities may have difficulty with various types of mental tasks. Intellectual disabilities, also known as developmental delay or mental retardation, are a group of disorders defined by diminished cognitive and adaptive development.
Color Blindness
A reduced ability to distinguish between certain colors, color blindness is usually classified as a vision disability.
Conformance Levels (A, AA, AAA)
The first thing to keep in mind is that all WCAG Success Criteria are important. Not from the perspective of a bleeding heart idealist, but that there are no “nice-to-haves”, these are all things that you should consider including in your web-based system.
  • Level A Success Criteria are those which will have a high impact on a broad array of user populations. In other words, they (usually) don’t focus on one type of disability only. They will also have the lowest impact on the presentation logic and business logic of the site or application. Finally, implementation of these requirements will typically be the easiest.
  • Level AA Success Criteria will also have a high impact for users. Sometimes only specific user populations will be impacted, but the impact is important. Adherence to these Success Criteria may impose changes to a system or site’s presentation logic or business logic.
  • Level AAA Success Criteria are often focused on improvements for specific user populations. They may be difficult or expensive to adhere to, depending on platform limitations. The benefit-to-cost ratio may be low enough to deprioritize these criterion.
Context-Sensitive Help
Help text that provides information related to the function currently being performed.
Contrast Ratio
In an accessibility context, this usually means the ratio between the color of text (or other important visual information) and the color of the background, which must meet minimum ratio levels to ensure legibility for visually-impaired/color blind users.
Decorative Image
An image that does not add information or meaning to content, is used for visual interest only, and are exempt from certain accessibility guidelines like as alternative text.
Descriptive Transcript
A descriptive transcripts includes both audio AND visual information needed to understand the content. Descriptive transcripts are required to provide content to people who are both deaf and blind. They are also used by people who process text information better than audio and video.
A physical or mental condition or function that restricts an individual's movements, senses, or abilities relative to the typical standards of a group. The term is used to refer to individual functioning, including physical impairment, sensory impairment, cognitive impairment, intellectual impairment, mental illness, and various types of chronic diseases.
If removed, would fundamentally change the information or functionality of the content, AND information and functionality cannot be achieved in another way that would conform. (SC 1.4.5 , SC 1.4.9, SC 2.2.3)
Focus Indicator
A visual indication of the currently selected element on a page, which enables users who are using keyboard access to know their location while navigating content.
Focus Order
The order in which focusable components of a web page receive focus in a way that preserves meaning and operability. Focus order is usually set programmatically.
Government Product/Service Accessibility Template (GPAT)
A GPAT is a simple tool to assist Federal contracting and procurement officials in fulfilling the market research requirements associated with the Section 508 standards. The GPAT is intended as a form to be included with government solicitations.
Images of Text
Text that has been rendered in a non-text form (e.g., an image) in order to achieve a particular visual effect. This does not include text that is part of a picture that contains significant other visual content. (SC 1.1.1 & SC 1.4.5)
IMS Global
The mission of this consortium is to advance technology that can affordably scale and improve educational participation and attainment. To ensure that the “Learning Impact” of technology-enabled innovation is achieved around the world, IMS’s community of educational institutions, suppliers, testing companies (including Pearson) and government organizations develops open interoperability standards (such as QTI and APIP), supports adoption with technical services, and encourages adoption through programs that highlight effective practices.
Individualized Stylesheets
An individualized style sheet is an assistive tool that allows users to customize the display of web content by writing their own CSS to override a site author’s styles. This is particularly useful for people with low vision disabilities who might need different fonts, font sizes, contrast or other modifications to read more comfortably. Individualized style sheets are added to the browser to override the original layout and style. (SC 1.3.2)
Keyboard Access
The ability to interact with a computer using a keyboard rather than a mouse. Users who have problems with fine motor skills or hand-eye coordination may prefer to use the keyboard to navigate through content. Common keyboard controls include using the Tab and Arrow keys to move from element to element (e.g. hyperlinks, buttons) and Enter/Spacebar to activate them.
Keyboard Trap
A problem that occurs when a user cannot navigate away from particular element/control on a page using keyboard access alone.
Learning Disability
A condition giving rise to difficulties in acquiring knowledge and skills to the level expected of those of the same age, especially when not associated with a physical disability.
Light Sensitivity
Extreme sensitivity to light (called photophobia) can cause severe eye pain and headaches for some people. This sensitivity can make it difficult or impossible to read content designed with light or bright backgrounds/color schemes. (SC 1.4.5)
Long Description
A HTML attribute (longdesc) that enables a longer piece of alternative text to be added to a non-text element than the alt attribute.
Luminance Contrast Ratio
The difference between the intensity of the light emitted from an object and its background, so that it can be read by people with moderately low vision who do not use contrast-enhancing assistive technology.
A form of XML used to describe the content and structure of mathematical notation on web pages and other documents. Using MathML enables complex equations to be more easily accessible to screen readers, and can help in the creation of alternative text.
Motor Impairment
Impairments that affect motor control, which refers to the capacity of the body, or of a body part to move, regardless of the goal and intended function of the movement produced.
Mouth Stick
A mouth stick is an assistive device used for typing by some people who experience severe mobility impairments. The mouth stick has a plastic or rubber feature at one end that is inserted into the mouth for controlling the movement, at the other end is a rubber tip for tapping on keyboard keys . (SC 2.1.2, SC 2.2.3)
Nemeth Braille
The Nemeth Braille Code for Mathematics is a Braille code for encoding mathematical and scientific notation linearly using standard six-dot Braille cells for tactile reading by the visually impaired.
Personal Needs & Preferences profile (PNP)
An APIP Standard for providing accessibility accommodations to students with personal needs and preferences, such as magnification, contrast, foreground color, background color, overlay color, audio text, audio graphics, non-visual audio, Braille, auditory calming, masking, breaks, and extended time. Each student's data file contains the accessibility preferences (if any) for that student, so that TestNav 8 can tailor, in real-time, the presentation of the question items to fit the accessibility needs of the user.
Programmatically Determined
Determined by software from author-supplied data provided in a way that different user agents, including assistive technologies, can extract and present this information to users in different modalities. (SC 1.3.1)
Reading Order
The order in which a screen reader reads content on a page. Note that the reading order is not always the same as visual order. The reading order is important in terms of navigation - screen reader users use keyboard commands to navigate around the content.
Real Time Captions
Real-time captions, or Computer Assisted Real-time Translation (CART), are created as an event takes place. A captioner (often trained as a court reporter or stenographer) uses a stenotype machine with a phonetic keyboard and special software. A computer translates the phonetic symbols into captions almost instantaneously and displays them on a laptop or on a large display screen. (SC 1.2.4)
Refreshable Braille Display
A device that can dynamically display braille translated from an electronic file. Displays range from 12 to 80 characters or cells. A braille reader is able to access educational materials from a variety of electronic file formats.
Responsive Design
An approach to web page creation that makes use of flexible layouts, flexible images and cascading style sheet media queries. The goal of responsive design is to build web pages or applications that detect the visitor's screen size and orientation and change the layout accordingly. (SC 1.4.4)
Screen Magnifier
A type of assistive technology that enables a user to enlarge all or part of the screen. Note that a screen magnifier is a separate piece of software and not the same as zoom functionality in user agents such as browsers.
Screen Reader
A type of assistive technology software application that is primarily used by people who are blind or low vision. It uses text-to-speech to help users read, navigate, and interact with digital content and user interfaces. Screen reader software also converts information into braille that can then be displayed on a refreshable braille device.
Section 508
The standards that were issued under Section 508 of the Rehabilitation Act which requires access for both members of the public and federal employees to such technologies when developed, procured, maintained, or used by federal agencies or any institution receiving federal funds.
Semantic Markup
The use of HTML markup to ensure content is identified by its meaning as opposed to just its appearance. Semantic markup enables screen readers to more accurately and usefully interpret the content of web pages.
Sensory Language
The use of shape, size, color, position or orientation to give the reader a visual image or layout to help describe controls or provide directions. (S.C. 1.3.3)
Speech To Text (STT)
The translation of spoken words into text. It is also known as automatic speech recognition, computer speech recognition, or just speech to text.
On-screen text for videos/animations provided for (hearing) users who do not understand the language of the dialogue being spoken. Note subtitles are different from captions, which are intended for deaf/hard-of-hearing users.
Success Criteria
For each guideline, testable success criteria are provided to allow WCAG 2.0 to be used where requirements and conformance testing are necessary such as in design specification, purchasing, regulation, and contractual agreements. In order to meet the needs of different groups and different situations, three levels of conformance are defined: A (lowest), AA, and AAA (highest).
Synchronized Caption File
A caption file, containing all of the speech and non-speech audio information needed to understand the media content, that includes time coding in order to synchronize the caption text with the audio content. (SC 1.2.2)
Tactile Graphic
Print images are represented in tactile form for readers who are blind or visually impaired. Tactile graphics are used to convey non-textual information such as maps, graphs, and diagrams. They are produced using a braille embosser, microcapsule paper, or hand produced by collage and/or tooling.
Text Alternative
Text Alternative (not to be confused with Alternative Text or “alt-text”) is additional text that is provided to convey the same information that is presented by non-text content (e.g., tables, charts, applets, media files, etc.).

Providing a text alternative also allows screen readers to convert the text into speech output. Additionally, having the information in text also makes it possible to translate the information into braille, sign language, pictures, or a simpler form of writing. (SC 1.1.1)
Text To Speech (TTS)
A form of speech synthesis that converts text into spoken voice output. Text to speech systems were first developed to aid the visually impaired or learning disabled by offering a computer-generated spoken voice that would "read" text to the user.
A text-based alternative to audio/video content that enables deaf/hard-of-hearing users to access the content.
User Agent
A proxy that acts on behalf of or supports users with disabilities, particularly to increase accessibility to Web content by identifying system information. User agents include operating systems, web browsers, media players, and assistive technologies for accessibility purposes. (add audio browser as an example)
Vision Impairment
Blindness or low vision are types of visual impairments, not necessarily limited to distance vision. Low vision applies to all individuals with sight who are unable to read the newspaper at a normal viewing distance, unable to be improved with corrective lenses or surgery.
Visually Customizable
The font, size, color, and background can be set. (SC 1.4.5)
Voluntary Product Accessibility Template (VPAT)
A VPAT is a vendor-generated statement (using the required template) that provides relevant information on how a vendor's product or service claims to conform to the Section 508 Standards.
Web Accessibility Initiative: Accessible Rich Internet Applications (WAI-ARIA) is a technical specification developed by the World Wide Web Consortium (W3C) to increase the accessibility of web pages, particularly those that feature rich interactive content and user interface components.
Web Content Accessibility Guidelines (WCAG)
Web Content Accessibility Guidelines version 2.0. A set of internationally-agreed recommendations and success criteria developed by the World Wide Web Consortium (W3C) to make web content more accessible for users with disabilities. These form the basis of the Pearson accessibility guidelines.
White (Negative) Space
“White” or “Negative” Space refers to any empty space between text, images and other site content. White space is not always white; it may be another color - depending on the background color used. (SC 1.4.8)