The HTML Definition Element (<dfn>) represents the defining instance of a term.

HTML5 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.
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 parent elements Any element that accepts phrasing content.
DOM interface HTMLElement


This element includes the global attributes.

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


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 worldwide.</p>

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
WHATWG 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

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 1.0 (1.7 or earlier) (Yes) (Yes) (Yes)
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) 1.0 (1.0) (Yes) (Yes) (Yes)

See also

Document Tags and Contributors

 Last updated by: Sheppy,