If you're familiar with the verb to "indicate," then indicator should be no problem. An indicator points to, suggests, or shows something. The arrow on a street sign is an indicator telling you which way to go.
An indicator is a measurement or value which gives you an idea of what something is like. ...vital economic indicators, such as inflation, growth and the trade gap. The number of wells is a fair indicator of the demand for water.
Synonyms: (informal) blinker, directional, directional signal, direction indicator, trafficator, turn indicator, (chiefly US) turn signal A bird, the honeyguide. (crosswording) A codeword that marks the use of a specific cryptic device. quotations
Definition of indicator noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.
in•di•ca•tor /ˈɪndɪˌkeɪtɚ/ n. [countable] a person or thing that indicates. Mechanical Engineering a pointing device, as a needle on the dial of a measuring instrument: The indicator showed 120 miles an hour. Mechanical Engineering a light on a car that flashes to show which way the car will turn.
indicator noun Something visible or evident that gives grounds for believing in the existence or presence of something else: