Akademik

a blinking light on a motor vehicle that indicates the direction in which the vehicle is about to turn

: an instrument for indicating either the amount or the rate of turn of an airplane about its vertical axis — compare relative inclinometer

a flight instrument that indicates the angular rate of turn of an aircraft about its vertical axis. Cf. bank-and-turn indicator.

[1915-20]

turn indicator,

1. a gyroscopic device that indicates in degrees per unit of time any turning movement about the vertical axis of an airplane.

2. one of the lights on the front and rear, and sometimes the sides, of a motor vehicle for signaling turns; turn signal.