A contextual popup that displays a description for an element.
The tooltip typically becomes visible in response to a mouse hover, or after the owning element receives keyboard focus. In each of these cases, authors SHOULD display the tooltip after a short delay. The use of a WAI-ARIA tooltip is a supplement to the normal tooltip behavior of the user agent.
Note: Typical tooltip delays last from one to five seconds.
Authors SHOULD ensure that elements with the role tooltip are referenced through the use of aria-describedby by the time the tooltip is displayed.