Meaning : 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.
Synonyms : index, index number, indicant
Meaning : A signal for attracting attention.
Meaning : A device for showing the operating condition of some system.
Meaning : (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.