Each command in ME'scope has a Tool associated with it.
A Tool is a graphical button that accompanies the command in its menu
A Tool Tip is a brief description of a command (typically its menu location and name)
When this command is checked, the display of Tool Tips is enabled.
Click on a window to make it active
Hover the mouse pointer over any Tool on a Toolbar or the Ribbon to display its Tool Tip
Structure Window Showing a Tool Tip.