lso have single definitions, used for terms upon their first occurence in a document:</p>

<h5>Heading level 5</h5>
<p>While they are essential reading material for our job, the <dfn><abbr title="World Wide Web Consortium">W3C</abbr></dfn>
  specifications are not exactly George R. R. Martin-level reading material.</p>

<p>Now to the <code>mark</code> element. This has a few useful applications:</p>

<ul>
  <li>useful for marking up interesting things in quotations (without altering the styling of text, eg 