indicator

Definitions

noun something which indicates how good or bad, hot or cold, etc. something is
noun a flashing light on a car which shows which way the driver is going to turn

noun something which shows the state of something else
noun a substance which shows that another substance is present
noun an organism whose presence or absence in an environment indicates conditions such as oxygen level or the presence of a contaminating substance

noun an instrument for recording engine cylinder pressure
noun a lamp on an instrument panel that lights up to show the operation of something, especially the illuminated arrow that indicates the direction in which a vehicle is about to turn

A component, circuit, device, instrument, piece of equipment, machine, or mechanism which conveys information pertaining to a magnitude or quantity. Said especially when the information is communicated visually. There many examples, including meters, indicator lamps, gauges, monitors, and so on.
A needle, dial, or other object which serves to convey information in a meter, gauge, or similar device or instrument.
A device, instrument, or piece of equipment which displays the information obtained by another device, instrument, or piece of equipment. For instance, a radar display.

noun the state of a process, as in closed access libraries showing the number of books ‘in’ and ‘out’

noun a substance which shows something, e.g. a substance secreted in body fluids which shows which blood group a person belongs to
noun something that serves as a warning or guide

16 definitions in context