<dfn>

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

Attributes

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.

Examples

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:

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

Result

Specifications

Browser compatibility

See also

• Elements related to definition lists: <dl>, <dt>, <dd>
• <abbr>