IN'DEX, n. plu. indexes, sometimes indices. [L. connected with idico, to show; in and dico.]1. That which points out; that which shows or manifests. Tastes are the indexes of the different qualities of plants.2. The hand that points to any thing, as the hour of the day, the road to a place.3. A table of the contents of a book. A table of references in an alphabetical order.4. In anatomy, the fore finger, or pointing finger.5. In arithmetic and algebra, that which shows to what power any quantity is involved; the exponent.6. The index of a globe, or the gnomon, is a little style fitted on the north pole, which by turning with the globe, serves to point to certain divisions of the hour circle.7. In music, a direct, which see.
Index expurgatory, in catholic countries, a catalogue of prohibited books.