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Understanding SC 3.1.3:Unusual Words (Level AAA)

In Brief

Users can identify and learn what unusual words mean.
What to do
Provide definitions for technical jargon and unusual terms.
Why it's important
More people, especially those with cognitive disabilities, can understand the meaning of content.

Success Criterion (SC)

A mechanism is available for identifying specific definitions of words or phrases used in an unusual or restricted way, including idioms and jargon.


Certain disabilities make it difficult to understand nonliteral word usage and specialized words or usage. Certain disabilities make it difficult to understand figurative language or specialized usage. Providing such mechanisms is vital for these audiences. Specialized information intended for non-specialist readers is encouraged to satisfy this Success Criterion, even when claiming only Single-A or Double-A conformance.


This Success Criterion may help people with cognitive, language and learning disabilities who:

  • have difficulty decoding words
  • have difficulty understanding words and phrases
  • have difficulty using context to aid understanding

It would also help people with visual disabilities who:

  • lose context when zoomed-in with a screen magnifier


Text that includes a definition for a word used in an unusual way
Organize the list or "cascade" of dictionaries and other resources so that the definition search will find the intended definitions instead of displaying definitions from other sources in the "cascade." (The "cascade" lists the dictionaries and other reference materials in the order most likely to bring up the right definition. This controls the order to follow when searching for definitions.)
Including definitions in the glossary
WCAG 2.0 uses the word "text" in a specific way. Thus, when the word "text" is used within WCAG 2.0 it is linked to the definition of "text" provided in a glossary within the same Web page.
The specific definition of a word is provided at the bottom of the page
The internal link from the word to the corresponding definition is also provided within the page.

Related Resources

Resources are for information purposes only, no endorsement implied.


The inclusion of a product or vendor name in the list below does not constitute an endorsement by the Web Content Accessibility Guidelines Working Group or the Web Accessibility Initiative of the World Wide Web Consortium. This list is provided simply for convenience and to give users an idea of what resources may be available


Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. However, it is not necessary to use these particular techniques. For information on using other techniques, see Understanding Techniques for WCAG Success Criteria, particularly the "Other Techniques" section.

Sufficient Techniques

Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.

Situation A: If the word or phrase has a unique meaning within the Web page:

Situation B: If the word or phrase means different things within the same Web page:

Key Terms

assistive technology

hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents


Functionality provided by assistive technology includes alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible).


Assistive technologies often communicate data and messages with mainstream user agents by using and monitoring APIs.


The distinction between mainstream user agents and assistive technologies is not absolute. Many mainstream user agents provide some features to assist individuals with disabilities. The basic difference is that mainstream user agents target broad and diverse audiences that usually include people with and without disabilities. Assistive technologies target narrowly defined populations of users with specific disabilities. The assistance provided by an assistive technology is more specific and appropriate to the needs of its target users. The mainstream user agent may provide important functionality to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles.


satisfying all the requirements of a given standard, guideline or specification


phrase whose meaning cannot be deduced from the meaning of the individual words and the specific words cannot be changed without losing the meaning


Idioms cannot be translated directly, word for word, without losing their (cultural or language-dependent) meaning.


words used in a particular way by people in a particular field


process or technique for achieving a result


The mechanism may be explicitly provided in the content, or may be relied upon to be provided by either the platform or by user agents, including assistive technologies.


The mechanism needs to meet all success criteria for the conformance level claimed.


series of user actions where each action is required in order to complete an activity

relied upon

the content would not conform if that technology is turned off or is not supported


mechanism for encoding instructions to be rendered, played or executed by user agents


As used in these guidelines "Web Technology" and the word "technology" (when used alone) both refer to Web Content Technologies.


Web content technologies may include markup languages, data formats, or programming languages that authors may use alone or in combination to create end-user experiences that range from static Web pages to synchronized media presentations to dynamic Web applications.

used in an unusual or restricted way

words used in such a way that requires users to know exactly which definition to apply in order to understand the content correctly

user agent

any software that retrieves and presents Web content for users

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