Definition of "index" in English

noun

1. An alphabetical listing of items and their location.

   • The index of a book lists words or expressions and the pages of the book upon which they are to be found.
   • He isn't able to find the index of the book.

2. The index finger; the forefinger.

3. A movable finger on a gauge, scale, etc.

4. (typography) A symbol resembling a pointing hand, used to direct particular attention to a note or paragraph.

5. That which points out; that which shows, indicates, manifests, or discloses.

6. A sign; an indication; a token.

7. (linguistics) 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.

8. (economics) A single number calculated from an array of prices or of quantities.

9. (sciences) A number representing a property or ratio; a coefficient.

10. (mathematics) A raised suffix indicating a power.

11. (computing, especially programming and databases) An integer or other key indicating the location of data, e.g. within an array, vector, database table, associative array, or hash table.

12. (computing, databases) A data structure that improves the performance of operations on a table.

13. (algebra, index of a subgroup) The number of cosets that exist.

    • The index of 2ℤ in ℤ is 2.

14. (obsolete) A prologue indicating what follows.

verb

1. (transitive) To arrange an index for something, especially a long text.

   • MySQL does not index short words and common words.

2. To inventory; to take stock.

3. (chiefly economics) To normalise in order to account for inflation; to correct for inflation by linking to a price index in order to maintain real levels.

4. To measure by an associated value.

5. (linguistics, transitive) To be indexical for (some situation or state of affairs); to indicate.

6. (computing) To access a value in a data container by an index.

7. (mechanical engineering, transitive) To use a mechanism to move an object to a precise location.