#1 indicator n. [index, index number, indicant] 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. wn
#2 indicator n. a signal for attracting attention. wn
#3 indicator n. a device for showing the operating condition of some system. wn
#4 indicator n. (chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction. wn
vizzz