Revision 1033804 of <dfn>

<h2 id="Summary">Summary</h2>

<p>The&nbsp;<em>HTML Definition Element</em>&nbsp;(<strong>&lt;dfn&gt;</strong>) represents the defining instance of a term.</p>

<div class="note"><strong>HTML5 Usage Notes:</strong>

<ul>
 <li>The <code>&lt;dfn&gt;</code> element marks the term being defined; the definition of the term should be given by the surrounding {{HTMLElement("p")}}, {{HTMLElement("section")}} or definition list group (usually a {{HTMLElement("dt")}}, {{HTMLElement("dd")}} pair).</li>
 <li>The exact value of the term being defined is determined by the following rules:
  <ol>
   <li>If the <code>&lt;dfn&gt;</code> element has a <code><strong>title</strong></code> attribute, then the term is the value of that attribute.</li>
   <li>Else, if it contains only an {{HTMLElement("abbr")}} element with a {{htmlattrxref("title", "abbr")}} attribute, then the term is the value of that attribute.</li>
   <li>Otherwise, the text content of the <code>&lt;dfn&gt;</code> element is the term being defined.</li>
  </ol>
 </li>
</ul>
</div>

<table class="properties">
 <tbody>
  <tr>
   <th scope="row"><a href="/en-US/docs/HTML/Content_categories" title="HTML/Content_categories">Content categories</a></th>
   <td><a href="/en-US/docs/HTML/Content_categories#Flow_content" title="HTML/Content categories#Flow content">Flow content</a>, <a href="/en-US/docs/HTML/Content_categories#Phrasing_content" title="HTML/Content categories#Phrasing content">phrasing content</a>, palpable content.</td>
  </tr>
  <tr>
   <th scope="row">Permitted content</th>
   <td><a href="/en-US/docs/HTML/Content_categories#Phrasing_content" title="HTML/Content_categories#Phrasing_content">Phrasing content</a>, but no {{HTMLElement("dfn")}} element must be a descendant.</td>
  </tr>
  <tr>
   <th scope="row">Tag omission</th>
   <td>{{no_tag_omission}}</td>
  </tr>
  <tr>
   <th scope="row">Permitted parent elements</th>
   <td>Any element that accepts <a href="/en-US/docs/HTML/Content_categories#Phrasing_content" title="HTML/Content_categories#Phrasing_content">phrasing content</a>.</td>
  </tr>
  <tr>
   <th scope="row">DOM interface</th>
   <td>{{domxref("HTMLElement")}}</td>
  </tr>
 </tbody>
</table>

<h2 id="Attributes">Attributes</h2>

<p><span style="line-height:21px">This element includes the&nbsp;</span><a href="https://developer.mozilla.org/en-US/docs/HTML/Global_attributes" style="line-height: 21px;" title="HTML/Global attributes">global attributes</a><span style="line-height:21px">.</span></p>

<p>In HTML5, the <code><strong>title</strong></code> attribute has special meaning, as noted above.</p>

<h2 id="Examples">Examples</h2>

<p>The following examples are valid in HTML5.</p>

<pre class="brush: html">
&lt;!-- Define "The Internet" --&gt;
&lt;p&gt;&lt;dfn id="def-internet"&gt;The Internet&lt;/dfn&gt; is a global system of interconnected networks that use the Internet Protocol Suite (TCP/IP) to serve billions of users worldwide.&lt;/p&gt;
</pre>

<p>Later in the same document:</p>

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

<h3 id="Result">Result</h3>

<p>{{ EmbedLiveSample('Examples', '600', '150', '', 'Web/HTML/Element/dfn') }}</p>

<h2 id="Specifications" name="Specifications">Specifications</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('HTML WHATWG', 'text-level-semantics.html#the-dfn-element', '&lt;dfn&gt;')}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td>&nbsp;</td>
  </tr>
  <tr>
   <td>{{SpecName('HTML5 W3C', 'text-level-semantics.html#the-dfn-element', '&lt;dfn&gt;')}}</td>
   <td>{{Spec2('HTML5 W3C')}}</td>
   <td>&nbsp;</td>
  </tr>
  <tr>
   <td>{{SpecName('HTML4.01', 'struct/text.html#h-9.2.1', '&lt;dfn&gt;')}}</td>
   <td>{{Spec2('HTML4.01')}}</td>
   <td>&nbsp;</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoDesktop("1.0")}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoMobile("1.0")}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li>Elements related to definition lists: {{HTMLElement("dl")}}, {{HTMLElement("dt")}}, {{HTMLElement("dd")}}</li>
 <li>{{HTMLElement("abbr")}}</li>
</ul>

<p>{{HTMLRef}}</p>