(in a nonfiction book, monograph, etc.) a more or less detailed alphabetical listing of names, places, and topics along with the numbers of the pages on which they are mentioned or discussed, usually included in or constituting the back matter.
2.
a sequential arrangement of material, especially in alphabetical or numerical order.
3.
something used or serving to point out; a sign, token, or indication: a true index of his character.
4.
something that directs attention to some fact, condition, etc.; a guiding principle.
5.
a pointer or indicator in a scientific instrument.
the integern in a radical defining the n-th root: ∛ is a radical having index three.
c.
a subscript or superscript indicating the position of an object in a series of similar objects, as the subscripts 1, 2, and 3 in the series x1, x2, x3.
(usually initial capital letter) any list of forbidden or otherwise restricted material deemed morally or politically harmful by authorities: an Index of disapproved books relating to Communism.
Economics. to adjust (wages, taxes, etc.) automatically according to changes in the cost-of-living level or another economic indicator, especially to offset inflation.
a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.