<hgroup> is a new HTML5 element. It groups a set of <h1> to <h6> elements, usually in the <header> section. <header> <hgroup> <h2>Human diseases caused by viruses</h2> <h3>AIDS</h3> </hgroup> </header>
<header> <hgroup> <h2>Human diseases caused by viruses</h2> <h3>AIDS</h3> </hgroup> </header>