INDICATOR, someone who or that which indicates [n]
A thing, esp. a trend or fact, that indicates the state or level of something
A device providing specific information on the state or condition of something, in particular
A gauge or meter of a specified kind
INDICATOR [n]
A turn signal
A compound that changes color at a specific pH value or in the presence of a particular substance and can be used to monitor acidity, alkalinity, or the progress of a reaction
An animal or plant species that can be used to infer conditions in a particular habitat