A Tooltip is an informative message that appears when a user interacts with a user interface element, the target. Tooltips are initiated in one of two ways: By hovering the target element with a mouse cursor or through the focus with a keyboard. In turn, Tooltips disappear when the mouse leaves the target element, or the keyboard focus is removed from the target.

Because a hover gesture or keyboard focus initiates tooltips, they can be used only on devices with a mouse or keyboard. They are not available on touch devices.