Labels can be used to provide context for information. For example, if we have a primary and secondary navigation, we can use arial-label to distinguish between them.
<div role="navigation" aria-label="Primary">
<ul><li>...a list of links here ...</li></ul>
</div>
<div role="navigation" aria-label="Secondary">
<ul><li>...a list of links here ...</li> </ul>
</div>