Thesaurus

(n) : an alphabetical listing of items and their location; for example, the index of a book lists words or expressions and the pages of the book upon which they are to be found; a type of noun where the meaning of the form changes with respect to the context. E.g., 'Today's newspaper' is an indexical form since its referent will differ depending on the context. See also icon and symbol

(v) : to arrange an index for something, especially a long text