Meaning

noun a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time

noun a signal for attracting attention

noun a device for showing the operating condition of some system

originFrom Late Latin indicātor (“one who points out”), from Latin indicō (“point out”). By surface analysis, indicate + -or; see indicate.

Etymology from Wiktionary, CC BY-SA 3.0