Meaning of INDICATOR in English
n.1 a person or thing that indicates.
2 a device indicating the condition of a machine etc.
3 a recording instrument attached to an apparatus etc.
4 a board in a railway station etc. giving current information.
5 a device (esp. a flashing light) on a vehicle to show that it is about to change direction.
6 a substance which changes colour at a given stage in a chemical reaction.
7 Physics & Med. a radioactive tracer.
Oxford English vocab. Оксфордский английский словарь. 2012