The HTML <dfn> element represents the defining instance of a term.

Content categories Flow content, phrasing content, palpable content.
Permitted content Phrasing content, but no <dfn> element must be a descendant.
Tag omission None, both the starting and ending tag are mandatory.
Permitted parents Any element that accepts phrasing content.
Permitted ARIA roles Any
DOM interface HTMLElement


This element's attributes include the global attributes.

In HTML5, the title attribute has special meaning, as noted below.

Usage notes

  • The <dfn> element marks the term being defined; the definition of the term should be given by the surrounding <p>, <section> or definition list group (usually a <dt>, <dd> pair).
  • The exact value of the term being defined is determined by the following rules:
    1. If the <dfn> element has a title attribute, then the term is the value of that attribute.
    2. Else, if it contains only an <abbr> element with a title attribute, then the term is the value of that attribute.
    3. Otherwise, the text content of the <dfn> element is the term being defined.


The following examples are valid in HTML5.

<!-- Define "The Internet" -->
<p><dfn id="def-internet">The Internet</dfn> is a global
system of interconnected networks that use the Internet
Protocol Suite (TCP/IP) to serve billions of users

Later in the same document:

  <!-- Define "World-Wide Web" and reference
       definition for "the Internet" -->
      <abbr title="World-Wide Web">WWW</abbr>
  <dd>The World-Wide Web (WWW) is a system of
  interlinked hypertext documents accessed on
  <a href="#def-internet">the Internet</a>.</dd>



Specification Status Comment
HTML Living Standard
The definition of '<dfn>' in that specification.
Living Standard  
The definition of '<dfn>' in that specification.
HTML 4.01 Specification
The definition of '<dfn>' in that specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes1 Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support Yes Yes Yes4 Yes Yes Yes

See also

Document Tags and Contributors

 Last updated by: teoli,