Index (: indexes or indices) most commonly refers to:

• Index (publishing), an organized list of information in a publication

• Web indexing, Internet indexing

• An index, a key in an associative array

Index may also refer to:

Arts, entertainment, and media

Fictional entities

• Index (A Certain Magical Index), a character in the light novel series A Certain Magical Index

• The Index, an item on the Halo Array in the Halo video game series

Periodicals and news portals

• Index Magazine, a publication for art and culture

• Index.hr, a Croatian online newspaper

• index.hu, a Hungarian-language news and community portal

• The Index (Kalamazoo College), a student newspaper

• The Index, an 1860s European propaganda journal created by Henry Hotze to support the Confederate States of America

• Truman State University Index, a student newspaper

• The Index: A Weekly Paper Devoted to Free Religion (1870–1886), the semi-official periodical of the Free Religious Association

Other arts, entertainment and media

• The Index (band)

• Indexed, a Web cartoon by Jessica Hagy

• Index, album by Ana Mena

Business enterprises and events

• Index (retailer), a former UK catalogue retailer

• INDEX, a market research fair in Lucknow, India

• Index Corporation, a Japanese video game developer

Finance

• Index fund, a collective investment scheme

• Stock market index, a statistical average of prices of selected securities

Places in the United States

• Index, Arkansas, an unincorporated community

• Index, Kentucky, an unincorporated community

• Index, Missouri, a ghost town

• Index, New York, a hamlet in Hartwick and Otsego, New York

• Index, Virginia, an unincorporated community

• Index, Washington, a town

• Index, West Virginia, an unincorporated community

Publishing and library studies

• Index (typography), a hand- or fist-shaped punctuation mark

• Bibliographic index, a regularly updated publication that lists articles, books, or other information items

• Citation index

• The Index, colloquial name for the List of Media Harmful to Youth and Adolescents (Germany)

• Index card, used for recording and storing small amounts of data

• Index Librorum Prohibitorum, a list of publications which the Catholic Church censored

• Index on Censorship, a publishing organization that campaigns for freedom of expression, or its magazine of the same name

• Subject indexing, describing the content of a document by keywords

• Thumb index, a round cut-out in the pages of a publication

Science, technology, and mathematics

Computer science

• , a character in Unicode

• Index, the dataset maintained by search engine indexing

• Array index, an integer pointer into an array data structure

• BitTorrent index, a list of .torrent files available for searches

• Database index, a data structure that improves the speed of data retrieval

• Index mapping of raw data for an array

• Index register, a processor register used for modifying operand addresses during the run of a program

• Indexed color, in computer imagery

• Indexed Sequential Access Method (ISAM), used for indexing data for fast retrieval

• Lookup table, a data structure used to store precomputed information

• Site map, or site index, a list of pages of a web site accessible to crawlers or users

• Web server directory index, a default or index web page in a directory on a web server, such as index.html

Economics

Index (economics), a single number calculated from an array of prices and quantities

• Price index, a typical price for some good or service

Mathematics and statistics

• Index, the position of an element in a sequence

• Index, a number or other symbol that specifies an element of an indexed family or set

• Index, an element of an index set

• Index, the label of a summand in Σ-notation of a summation

Algebra

• Index of a subgroup, the number of a subgroup's left cosets

• Index, the degree of an nth root

• Index of a linear map, the dimension of the map's kernel minus the dimension of its cokernel

• Index of a matrix

• Index of a real quadratic form

Analysis

• Index, the winding number of an oriented closed curve on a surface relative to a point on that surface

• Diversity index, a measure of distribution or variety in fields such as ecology or information science

• Index of a vector field, an integer that helps to describe the behaviour of a vector field around an isolated zero

Number theory

• Index, or the discrete logarithm of a number

Statistics

Index (statistics), a type of aggregate measure

• Scale (social sciences), a method of reporting data in social sciences, sometimes called an index

Other uses in science and technology

• Indexicality, in linguistics, the phenomenon of a sign pointing to some object in the context in which it occurs

• Indexing (motion), in mechanical engineering and machining, movement to a precisely known location

• Index (physical sciences), a synonym for ratio

Other uses

• INDEX, earlier name for the Reimei satellite

• Index:, a Danish nonprofit organization that promotes Design for Life

• The Index (Dubai), a skyscraper

• Index (crater), a Moon crater

• In semiotics, an unintentional and non-arbitrary sign causally related to what it indicates, for example the smoke from a fire or the footprint of an animal.

See also

• Indexi, a Yugoslav rock band

• Indexer (disambiguation)

• Directory (disambiguation)