Index  —n. (pl. Indexes or indices) 1 alphabetical list of subjects etc. With references, usu. At the end of a book. 2 = *card index. 3 measure of prices or wages compared with a previous month, year, etc. (retail price index). 4 math. Exponent of a number. 5 pointer, sign, or indicator. —v. 1 provide (a book etc.) With an index. 2 enter in an index. 3 relate (wages etc.) To a price index.  indexation n. (in sense 3 of v.). [latin]