Revision 612275 of <dfn>

<h2 id="Summary">Summary</h2>
<p>The <strong>HTML <code>&lt;dfn&gt;</code> element</strong> (or <em>HTML Definition Element</em>) 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 <strong>title</strong> 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>
<ul class="htmlelt">
 <li><dfn><a href="/en-US/docs/HTML/Content_categories" title="HTML/Content_categories">Content categories</a></dfn> <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.</li>
 <li><dfn>Permitted content</dfn> <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.</li>
 <li><dfn>Tag omission</dfn> {{no_tag_omission}}</li>
 <li><dfn>Permitted parent elements</dfn> Any element that accepts <a href="/en-US/docs/HTML/Content_categories#Phrasing_content" title="HTML/Content_categories#Phrasing_content">phrasing content</a>.</li>
 <li><dfn>DOM interface</dfn> {{domxref("HTMLElement")}}</li>
</ul>
<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 <strong>title</strong> 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>
<!-- 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>
<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>
<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>