Index

Index (: indexes or indices) may refer to:

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

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

 * Bibliographic index, a regularly updated publication that lists articles, books, or other information items
 * Citation index
 * The Index, colloquial name for Germany's List of Media Harmful to Young People, published by the Bundesprüfstelle für jugendgefährdende Medien
 * 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
 * Index (publishing), an organized list of information in a publication
 * Index (typography), a hand- or fist-shaped punctuation mark
 * Subject indexing, describing the content of a document by keywords
 * Thumb index, a round cut-out in the pages of a publication
 * Web indexing, Internet indexing

Computer science

 * Index, a key in an associative array
 * Index (typography), a character in Unicode, its code is 132
 * 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 indexing, Internet indexing
 * 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, 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

 * Dental indices, standardized scoring systems for tooth problems
 * 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
 * Refractive index, a measurement of how light propagates through a material
 * Valve Index, a virtual reality headset

Other uses

 * INDEX, earlier name for the Reimei satellite
 * Index:, a Danish nonprofit organization which promotes Design for Life
 * The Index (Dubai), a skyscraper
 * Index (crater), a Moon crater