Turn indicator and Visual signal

Turn indicator noun - A blinking light on a motor vehicle that indicates the direction in which the vehicle is about to turn.

Visual signal and turn indicator are semantically related. In some cases you can use "Visual signal" instead a noun phrase "Turn indicator".

Visual signal noun - A signal that involves visual communication.

Turn indicator and visual signal are semantically related. Sometimes you can replace phrase "Turn indicator" with "Visual signal", this phrases are similar.