in·dex / ˈinˌdeks/ • n. (pl. -dex·es or esp. in technical use -di·ces / -dəˌsēz/ ) 1. an alphabetical list of names, subjects, etc., with references to the places where they occur, typically found at the end of a book. ∎  an alphabetical list by title, subject, author, or other category of a collection of books or documents, e.g., in a library. ∎  Comput. a set of items each of which specifies one of the records of a file and contains information about its address.2. an indicator, sign, or measure of something: exam results may serve as an index of the teacher's effectiveness. ∎  a figure in a system or scale representing the average value of specified prices, shares, or other items as compared with some reference figure: the hundred-shares index closed down 9.3. ∎  a pointer on an instrument, showing a quantity, a position on a scale, etc. ∎  a number giving the magnitude of a physical property or another measured phenomenon in terms of a standard: the oral hygiene index was calculated as the sum of the debris and calculus indices.3. Math. an exponent or other superscript or subscript number appended to a quantity.4. Printing a symbol shaped like a pointing hand, typically used to draw attention to a note.5. (the Index) short for Index Librorum Prohibitorum.• v. [tr.] 1. record (names, subjects, etc.) in an index: the list indexes theses under regional headings. ∎  provide an index to.2. link the value of (prices, wages, or other payments) automatically to the value of a price index: the Supreme Soviet passed legislation indexing wages to prices.3. [intr.] [often as n.] (indexing) (of a machine or part of one) rotate or otherwise move from one predetermined position to another in order to carry out a sequence of operations.DERIVATIVES: in·dex·a·ble adj.in·dex·a·tion / ˌindekˈsāshən/ n.in·dex·er n.in·dex·i·ble adj.