an instrumentality invented for a particular purpose

an indicator that announces which electrical circuit has been active (as on a telephone switchboard)

(computer science) indicator consisting of a movable spot of light (an icon) on a visual display; moving it allows the user to point to commands or screen positions

the circular graduated indicator on various measuring instruments

an indicator of the amount of fuel remaining in a vehicle

indicator provided by the stationary arm whose shadow indicates the time on the sundial