The term 'turn indicator' refers to the various signals used to indicate a vehicle is turning. The most common of these signals are an ARROW (5 letters), SIGNAL (6 letters) and taillight (9 letters). An ARROW is typically a sign or symbol that points in the direction of the turn. A SIGNAL is a visual or audible cue that indicates a turn is about to occur. Finally, a taillight is a light on the back of a vehicle that illuminates when the vehicle is turning. All three of these signals are used to indicate a vehicle is turning and are collectively referred to as turn indicators.