ETYM Latin: cf. French index. Related to Indicate, Diction.
1. 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; SYN. index number, indicant, indicator.
2. A numerical scale used to compare variables with one another or with some reference number.
3. An alphabetical listing of names and topics along with page numbers where they are discussed.
4. The finger next to the thumb; SYN. index finger, forefinger.