See indicator in Webster's New World College Dictionary a person
or thing that indicates; specif., any device, as a gauge, dial,
register, or pointer, that measures or records and visibly
indicates an apparatus that diagrams the varying fluid pressure
of an engine in operation any of various substances used to
indicate the acidity or alkalinity of a solution, the beginning
or end of a chemical reaction, the presence of certain
substances, etc., by changes in color a statistic, as the
unemployment rate, used to measure economic or social conditions
Ecol. a species of plant or animal, or a community, whose
occurrence serves as evidence that certain environmental
conditions exist See indicator in American Heritage Dictionary 4
One that indicates, especially: a. A pointer or an index. b. An
instrument used to monitor the operation or condition of an
engine, furnace, electrical network, reservoir, or other
physical system; a meter or gauge. c. The needle, dial, or other
registering device on such an instrument. Ch