An element of a graphical user interface in the form of a box of text that appears when a cursor is made to hover over an item; normally used to explain the function of the item.(noun)
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Use "tooltip" in a sentence
"ControlFocus, SysListView321, \% MainWnd\%; removes long name tooltip"
"A tooltip is a box that appears when you hover your cursor over an element like a hyperlink."
"Fixed: Rename tooltip on llPushObject icon in the menu bar to read "No Pushing""