Glossary of Accessibility Terms

What do we mean when we use these common accessibility terms?

The field of accessibility comes with a lot of acronyms and jargon. It can occasionally leave even the most experienced of us scratching our heads. While not exhaustive, this glossary of terms, defined in the context of web development, should equip you to understand the most frequently encountered head-scratchers.

A, AA, and AAA conformance levels

The WCAG guidelines have three conformance levels. Level A is the minimum level. Level AA is recommended for most websites and is required by many laws and regulations. Level AAA is the highest conformance level and provides enhanced accessibility; achieving AAA conformance for all content may not be possible.

Often pronounced as “alley,” this is a numeronym for the word “accessibility.” A numeronym is a type of abbreviation where a number is used to replace some of the letters within a word. In this case, the number 11 stands for the middle eleven letters of the word “accessibility.” This shorthand saves space or reduces typing, for example, in social media posts and domain names.

Accessibility audit

This is a comprehensive review of a product’s accessibility, usually conducted by an expert.

Accessibility testing

Accessibility testing involves testing a product against a set of accessibility criteria, such as the Web Content Accessibility Guidelines (WCAG). This can involve automated tools, manual evaluation, and user testing by individuals with disabilities.

Accessible name

Text that is programmatically associated with an element on a webpage, such as a button, link anchor, or form control, can be used by assistive technologies to identify the element.

Accessible Rich Internet Applications (ARIA)

ARIA is a standard for a set of HTML attributes defining roles, states, and properties that can be added to control the way webpage content is interpreted by assistive technology like screen readers.

Alternative text (alt text)

Text alternative for images and other visual content. For example, users who rely on screen readers will hear the alt text provided by webpage authors to describe an image.

Americans with Disabilities Act (ADA)

The ADA is a federal civil rights law in the United States that prohibits discrimination against individuals with disabilities.

Assistive technology (AT)

Any equipment or software used to improve the functional capabilities of people with disabilities. Examples are screen reader software, braille displays, switch devices, eye-tracking, screen magnifiers, and voice control software.

Attention deficit hyperactivity disorder (ADHD)

ADHD is a neuro-developmental condition that affects many children and adults. It’s characterized by difficulty focusing, sustaining attention, restlessness, and impulsivity. The severity of symptoms can vary greatly between individuals, and ADHD can manifest differently in children and adults.

Audio description (AD)

Audio description is spoken narration played over a soundtrack to describe important visual details that cannot be understood from listening to the main soundtrack alone. It is most often used with closed captioning.

Autism Spectrum Disorder (ASD)

Sometimes referred to simply as “Autism,” (the DSM-5, a standard classification of disorders used by mental health professionals in the United States, merged previously separate diagnoses into the single diagnosis of ASD) this is a developmental condition that affects how people process information, interact with the world, and communicate. It’s a spectrum disorder, meaning symptoms can vary widely in severity and presentation from person to person.

Barriers

This refers to any obstacle that prevents users with disabilities from accessing or interacting effectively with websites. Barriers can be technical, presentation-related, or content-based.

Braille

Braille refers to a tactile writing system designed for people who are blind or have low vision. Braille is not a language but an encoding that can be used to express other languages (there are braille codes for over 133 languages). Note that “Braille,” with an uppercase B, refers to the writing system. In contrast, “braille,” with a lowercase b, refers to the tactile codes used to represent a particular language using that system.

Braille display

A Braille display is a hardware device that translates information from a screen reader into braille characters for users to read.

Browse mode

In this screen reader mode, webpage content is read out as a virtual cursor moves down the webpage.

Cascading Style Sheets (CSS)

CSS is a language that controls the visual presentation of content on a webpage. It allows web developers to define styles to control things like font size, color schemes, layout, and spacing.

Closed captioning

A readable representation of the audio portion of a video, displayed on the screen in real-time, to provide access for users who cannot hear the audio. This includes dialogue and descriptions of sounds like music or sound effects that are necessary to understand the meaning. Contrast with subtitles, intended for viewers who speak a different language than the one spoken in the video.

Cognitive

The term “cognitive” refers to the mental processes used to understand and interact with web content. Cognitive disabilities can involve impairments to memory, learning, problem-solving, attention, and reading comprehension.

Color vision deficiency (CVD)

Often called “color blindness” this condition is estimated to affect 8% to 10% of the entire population. It is a spectrum of deficiencies, to varying degrees, in the ability to perceive colors. It can appear in different forms depending on the affected receptors in the eye, the most common of which is a decreased ability to distinguish red and green colors.

Conformance

In the context of accessibility requirements, this means meeting the requirements of an accessibility criterion or set of criteria.

Contrast

The difference in luminance (the perceived brightness) between two adjacent colors.

Deaf

This term may describe a person with significant hearing loss, including people who are severely hard of hearing or have lost most or all of their hearing. The term “deaf,” with a lowercase d, does not imply any specific communication method or cultural identity. In contrast, the term “Deaf,” with an uppercase D, is used by people who identify as part of a cultural community of Deaf people and often use sign language as their primary language.

Deafblind

Describes a combination, sometimes referred to as a “dual sensory” or “multi-sensory,” impairment that includes both sight and hearing loss. Like the individual conditions of deafness and blindness, deafblindness can occur on a range where either sense may be impaired to varying degrees.

Digital accessibility

Digital accessibility is a field of work focused on making digital content, such as webpages, mobile apps, and electronic kiosks, more accessible for people with disabilities.

Disability model

The perspective from which we define the concept of “disabled” which then shapes how we understand and respond to disabled people as a society. For example, the medical model defines disability in terms of a person’s condition and implies that addressing access needs should focus on managing a person’s mental or physical impairments; the social model, by contrast, considers the medical cause of a person’s impairment less relevant and instead focuses on reducing barriers created by society’s failure to accommodate access needs adequately.

Dyslexia

Dyslexia is a condition that primarily affects reading. People with dyslexia process information differently, specifically in relation to language; for example, in translating written letters into their corresponding sounds (phonemes).

Element

The individual building blocks of HTML. Elements are defined in the source code of a webpage. They can represent various types of content, such as headings of various levels (<h1>, <h2>, and so on), paragraphs (<p>), images (<img>), buttons (<button>), and link anchors (<a>).

Focus

Regarding keyboard navigation, the term “focus” refers to the part of a webpage that can currently be interacted with using keystrokes or assistive technology. It’s often indicated visually by an outline around the focused element. Users can navigate between focusable elements without using a mouse, for example, by pressing the tab key.

Forms mode

When a screen reader user navigates to a form input element on a webpage, the screen reader switches to this mode. In forms mode, the action of specific keystrokes changes to make interacting with form elements like text inputs, drop-downs, checkboxes, and buttons easier. Contrast with browse mode.

HTML

A markup language used for building webpages using so-called tags in the source code to define the structure and content for browsers and assistive technology to present to the user.

Informative

In the context of accessibility requirements, any content that provides information, additional guidance, or examples but which is not strictly part of the conformance criteria.

JavaScript (JS)

JavaScript is a programming language commonly used to add interactivity to websites. It allows developers to add bespoke dynamic features to user interfaces to a web page.

Keyboard accessibility

Keyboard accessibility refers to the ability to navigate and interact with a webpage using only a keyboard. Users may use a combination of input devices, including a keyboard, to interact with a web page. On devices with a keyboard, screen reader users are typically keyboard navigators.

Motor control

Refers to the ability to make precise or broad (“fine” or “gross”) movements to interact with a computer or similar device. This can affect the operation of a keyboard, mouse, touchscreen, and other input devices. Users with limited motor control may face barriers with tasks like typing, tapping or clicking small targets, or making specific gestures on a touchscreen.

Non-normative

In the context of accessibility requirements, “non-normative” means any criteria not required for conformance. This could include advisory techniques that are suggestions to improve accessibility but are not mandatory.

Normative

In the context of accessibility requirements, the term “normative” means any criteria that must be met for conformance.

Neurodiversity (ND)

Refers to the spectrum of natural brain function and information processing that fall outside what’s considered typical in the general population. Neurodiverse people may experience an uneven profile of abilities and impairments, and not every neurodiverse person considers themselves impaired. This is relevant when designing for users who have ADHD, ASD, or dyslexia, for example.

Platform

A combination of a user’s physical device, operating system, and software used to access web content and applications.

Progressive enhancement

Progressive enhancement is an approach to web design and development based on the idea of first ensuring that the core content and functionality are provided to as many users as possible and then optionally improving that experience for users of the most capable software or hardware.

Screen magnifier

Software that enlarges onscreen content to make it more visible to low-vision users.

A screen reader is software used to access information displayed on a screen so that it can be navigated and perceived by the user as synthesized speech or on a Braille display. They may be installed by the user or come built into the operating system.

Section 508

This is part of a federal law in the United States that requires federal agencies to make their electronic information and services accessible to people with disabilities.

Semantic HTML

The term “semantic” refers to the use of HTML markup to define elements and components in a way that reflects their logical meaning, not just their appearance.

A skip link is an in-page HTML link that allows users to bypass repeated content at the top of a website and jump directly to the main content of a webpage. It’s particularly helpful for users who rely on screen readers or keyboards to navigate.

Source order

This refers to the order in which elements appear within a webpage’s HTML source code. This is important because assistive technologies, like screen readers, rely on it to determine the reading and navigation order in which to present content to users.

Success criteria (SC)

In the context of accessibility requirements, a success criteria is a testable statement that describes what a web author must do to meet a particular accessibility goal. WCAG, for example, uses success criteria to define its recommendations to web page creators.

Switch device

A controller that allows users with limited movement to interact with their computer using a single switch, such as a button or joystick.

Text-to-speech (TTS)

Software that reads digital text aloud.

Transcript

A transcript is a text representation of the spoken content of audio or video. It may be relied upon by users who are deaf or hard of hearing but is also helpful for search engine optimization (SEO), non-native language speakers, and people who have difficulty with focus and attention.

User agent

Software that retrieves and displays web content for you. This is typically a web browser (like Chrome, Edge, Firefox, or Safari).

User interface (UI)

The (usually visual) presentation of elements and features that users interact with on a webpage. UI design has a significant impact on web accessibility.

Usability

The term usability refers to a combination of factors, such as how intuitive an interface is, how clearly and concisely the information is presented, and how efficiently a website functions. It’s not all functional; aesthetics and user enjoyment can indirectly impact usability. While usability focuses on making a website easy to use for everyone, accessibility refers specifically to the needs of users with disabilities

User experience (UX)

The overall perception and interaction of a person using a website or app.

Visually impaired

This describes a spectrum of vision conditions that impair a person’s ability to access information presented visually on a computer screen. This can encompass a range of conditions, including blindness, low vision, or other visual impairments. This is relevant when designing for users who cannot see details, perceive colors, or see on-screen text.

Voice recognition software

Software allowing users to control their computer (enter text or give commands, for example) using their voice enables hands-free operation. This is relevant when designing for users affected by Amyotrophic Lateral Sclerosis (ALS), Parkinson’s disease, or spinal cord injuries, for example.

Web Content Accessibility Guidelines (WCAG)

An internationally recognized standard for evaluating web accessibility. It is often referenced as a legal standard in accessibility laws and regulations.

World Wide Web Consortium (W3C)

The W3C is an international organization that plays a key role in developing standards, protocols, and guidelines to keep the Web open, accessible, and interoperable. It is the driving force behind ARIA and WCAG.