INDEX

n. pl. in·dex·es or in·di·ces (-d-sz)
Something that serves to guide, point out, or otherwise facilitate reference, especially:
An alphabetized list of names, places, and subjects treated in a printed work, giving the page or pages on which each item is mentioned.
A thumb index.
A table, file, or catalog.
Something that reveals or indicates; a sign: “Her face... was a fair index to her disposition” (Samuel Butler).
A character () used in printing to call attention to a particular paragraph or section. Also called fist, hand.
An indicator or pointer, as on a scientific instrument.

Mathematics. A number or symbol, often written as a subscript or superscript to a mathematical expression, that indicates an operation to be performed, an ordering relation, or a use of the associated expression.
A number derived from a formula, used to characterize a set of data.
Index Roman Catholic Church. A list formerly published by Church authority, restricting or forbidding the reading of certain books.

tr.v. in·dexed, in·dex·ing, in·dex·es
To furnish with an index: index a book.
To enter in an index.
To indicate or signal.
To adjust through indexation.