Definitions for "Tool tip"
A tiny yellow box that gives information when you rest your cursor in a certain place, eg, over a tool bar icon, without clicking or dragging.
a small, onscreen window ( not a popup) that provides relevant information when you position the mouse pointer over selected links and icons
a small text box that appears when you hold your mouse over a button or text field in the UI
Short descriptions of clickable objects.
a pop-up label that temporarily identifies an object