28 Website Accessibility Terms to Know in 2022

Jamie Juviler
Jamie Juviler


No matter the type of website you run or the industry that you’re in, prioritizing web accessibility is key to your success.

person using a laptop to browse web accessibility terms

Globally, around 15% of people experience some form of disability. This translates to a sizable portion of your audience who do not interact with your website the exact way you might imagine.

To ensure your website meets today’s standards for web accessibility, you’ll first need to understand the terminology. Accessibility is a big, dense area with a lot of jargon, acronyms, and codes — enough to steer a new website owner away from the topic altogether.

That’s why we’ve put together this glossary of 28 essential web accessibility terms any website owners should be aware of. By knowing the language, you’ll find it much easier to adopt accessibility principles on your own site and better serve visitors with disabilities.

Download Now: Free Website Accessibility Checklist


Section 508 is an amendment to the U.S. Rehabilitation Act of 1973 introduced 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.” Section 508 requires that information technology used or developed by a federal agency is accessible to people with disabilities.


A11y is an abbreviation for “accessibility.” The “11” stands for the 11 letters between the first letter “a” and the last letter “y.”


Accessibility measures the usability of a product or experience by people who experience disabilities. An accessible experience accommodates those with various impairments and limitations, including visual, auditory, cognitive, language, and learning. Accessibility practices are important for ensuring that all users have the same level of access to online content.


The Americans with Disabilities Act (ADA) is a U.S. federal law that “prohibits discrimination against people with disabilities in several areas, including employment, transportation, public accommodations, communications and access to state and local government’ programs and services.”

Alternative Information

Alternative information is content provided as a substitute for the original content, included if the original content is inaccessible to a portion of the audience. It must provide equivalent information to the original content in order to provide the same experience for disabled users. For example, captions provide a text alternative to audio for users with hearing impairments.

Alternative Text

Alternative text (or “alt text” for short) is a brief piece of text which describes the contents of an image. Alt text appears on a web page in place of an image if a screen reader is being used, or if the image fails to load in the browser.


ARIA (short for Accessible Rich Internet Applications) is a set of roles, states, and properties that are added to HTML elements as tags. ARIA tags describe the purpose of common interface elements that lack semantic HTML tags, such as notes, alerts, search bars, and menus. ARIA attributes enhance the accessibility of HTML for screen readers beyond what plain HTML can do.

Assistive Technology

Assistive technology is hardware or software that allows individuals with disabilities to interact with computers or computer-based systems more easily or efficiently. Common assistive technologies include screen readers, refreshable braille displays, screen magnification tools, and audio browsers.

Audio Browser

An audio browser is a web browser that provides text-to-speech functionality for blind and visually impaired users. An audio browser can identify page elements like headings, body text, and links to help users navigate websites.


According to the U.S. Centers for Disease Control and Prevention, a disability is “any condition of the body or mind (impairment) that makes it more difficult for the person with the condition to do certain activities (activity limitation) and interact with the world around them (participation restrictions).” Web accessibility seeks to address impairments of vision, hearing, movement, and cognition. Disabilities may be lifelong, or they may be temporary, such as the result of an injury.


A CAPTCHA — short for “Completely Automated Public Turing test to tell Computers and Humans Apart" — is a test to distinguish human users from computer agents to detect and prevent bot traffic on a website. CAPTCHAs may achieve this in a variety of ways, such as tracking mouse movements, asking users to identify images or text, or presenting a math problem to solve.


Captions are a visual representation of speech and sound through text displayed on a screen. Captions play in sync with a video to provide a text alternative for users with hearing impairments. There are two types of captions: closed captions, which may be turned off by the user, and open captions, which cannot be turned off as they are a part of the video itself.

Clickability Cue

A clickability cue is a visual signal that a page element can be clicked Clickability cues include color, text decoration (i.e., underlining), arrows, cursor shapes, and animations.

Color Contrast

Color contrast is the difference in light between two adjacent colors on a web page. If color contrast between two elements is insufficient, this hinders accessibility. For example, light-colored text over a white background may be difficult for people with visual impairments to read. WCAG recommends a color contrast ratio of at least 4.5:1 between text color and background color.


CSS, short for Cascading Style Sheets, is a popular coding language used to apply styling to web pages, typically used in conjunction with HTML.


Focus refers to the part of the web page that is currently receiving input from the keyboard. Web browsers typically indicate a focused element with a focus state, an outline around the selected element. Users can change the focused element with the tab key — this is called “tabbing through” a page.


Hierarchy is the organization of web page content by level of importance, often established with HTML heading elements (<h1>, <h2>, <h3>, and so on). Hierarchy helps screen reader users understand the structure of a web page and navigate efficiently.


HTML, short for HyperText Markup Language, is a coding language that defines the basic structure of web pages. Combined with CSS and JavaScript, HTML is the basis of all websites you use. Many accessibility measures involve writing HTML in such a way that aids assistive technology users.


JavaScript is a client-side scripting language. One of the three major front-end coding languages (alongside HTML and CSS), JavaScript controls the behavior of web pages. JavaScript can be used to make dynamic or interactive web pages, and to extend the behavior of a web page beyond static content.

Screen reader

A screen reader is an assistive technology that converts digital text into speech or braille output. Screen readers are used primarily by people with blindness or visual impairments to navigate web pages and computer software. Designing for screen reader accessibility is one of the primary aims of the Web Content Accessibility Guidelines (WCAG).

Semantic HTML

Semantic HTML (also called semantic markup) is HTML that communicates the meaning of its elements through the proper use of HTML tags. Semantic markup helps people using assistive technologies to understand the structure and components of a web page.

Success Criteria

For each guideline in the WCAG, there are multiple testable success criteria. Each success criterion is assigned a level of conformance: A (lowest conformance), AA, or AAA (highest conformance). Conformance level for each success criterion is determined by factors such as necessity and technical requirements.

Universal Design

Universal design is a philosophy of design focused on creating spaces and products that are accessible to all people, regardless of factors like age and ability. Universal design tries to meet the needs of as many people as possible with no changes made to the original design to accommodate for special cases — a design should, in theory, work for any user out-of-the-box.

For example, a company could create one version of its website for desktop users and a separate mobile version of the website for smartphone users. Or, with a universal design approach, the company would create one single website that works equally well when displayed across devices.


Usability measures how easily, effectively, and enjoyably a person uses and experiences a product. In terms of websites, usability measures the quality of the user experience when interacting with a web page. Accessibility is usability by people with disabilities.

User Agent

A user agent is any software that can access websites, including web browsers, mobile applications, extensions and plug-ins, and assistive technologies that retrieve and present web content to users.


The Web Accessibility Initiative (WAI) is a project led by the World Wide Web Consortium (W3C) to improve accessibility on the web. WAI develops tools, conducts research, and creates guidelines to promote a more accessible internet.


The Web Content Accessibility Guidelines (WCAG) are a set of documents developed by WAI that set technical standards for web content accessibility. The latest version is WCAG 2.1, published in 2018, which contains 13 guidelines under four principles: perceivable, operable, understandable, and robust. Each guideline contains one or more testable success criteria to achieve WCAG compliance. WCAG 2.1 also adds 17 additional success criteria from the previous version, WCAG 2.0, to better address mobile accessibility, people with low vision, and people with cognitive and learning disabilities.

Web Accessibility

Web accessibility is the practice of making websites usable for all visitors, including those with disabilities, impairments, and limitations. While the topic of accessibility may broadly apply to any product, space, or experience, web accessibility focuses specifically on websites and web applications. It involves meeting certain criteria to ensure that people with disabilities have an equivalent experience to non-disabled people.

To ensure your website meets the criteria for accessibility and provides the same delightful user experience to everyone, you can download our free Website Accessibility Checklist:

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A checklist to help you make your website more accessible and usable.