Index (or its plural form indices) may 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 a Halo megastructure in the ''Halo'' series of video games

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 Index (or its plural form indices) may 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 a Halo megastru ...

, a market research fair in Lucknow, India * Index Corporation, a Japanese video game developer

Finance

* Index fund, a collective investment scheme *

Stock market index In finance, a stock index, or stock market index, is an index that measures a stock market, or a subset of the stock market, that helps investors compare current stock price levels with past prices to calculate market performance. Two of the ...

, 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 Index is a hamlet in the Hartwick, New York, Town of Hartwick, New York, and partially in Otsego, New York, Town of Otsego, Otsego County, New York, Otsego County, New York, United States. It is located at the corner of List of county routes in O ...

, a hamlet in Hartwick and Otsego, New York * Index, Virginia, an unincorporated community *

Index, Washington Index is a town in Snohomish County, Washington, United States. The population was 178 at the 2010 census. History Prior to settlement by White Americans, the Skykomish lived in the area between Sultan and Index. The Skykomish had a village al ...

, 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 An index card (or record card in British English and system cards in Australian English) consists of card stock (heavy paper) cut to a standard size, used for recording and storing small amounts of discrete data. A collection of such cards e ...

, used for recording and storing small amounts of data * ''

Index Librorum Prohibitorum The ''Index Librorum Prohibitorum'' ("List of Prohibited Books") was a list of publications deemed heretical or contrary to morality by the Sacred Congregation of the Index (a former Dicastery of the Roman Curia), and Catholics were forbidden ...

'', a list of publications which the Catholic Church censored *

Index on Censorship Index on Censorship is an organization campaigning for freedom of expression, which produces a quarterly magazine of the same name from London. It is directed by the non-profit-making Writers and Scholars International, Ltd (WSI) in association w ...

, a publishing organization that campaigns for freedom of expression, or its magazine of the same name *

Index (publishing) An index (plural: usually indexes, more rarely indices; see below) is a list of words or phrases ('headings') and associated pointers ('locators') to where useful material relating to that heading can be found in a document or collection of doc ...

, 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

Science, technology, and mathematics

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 In computer science, a lookup table (LUT) is an array that replaces runtime computation with a simpler array indexing operation. The process is termed as "direct addressing" and LUTs differ from hash tables in a way that, to retrieve a value v wi ...

, 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 * Webserver directory index, a default or index web page in a directory on a web server, such as index.html

Economics

Index (economics) In Statistics, Economics and Finance, an index is a statistical measure of change in a representative group of individual data points. These data may be derived from any number of sources, including company performance, prices, productivity, and ...

, 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 ''n''th 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 In mathematics, a quadratic form is a polynomial with terms all of degree two ("form" is another name for a homogeneous polynomial). For example, :4x^2 + 2xy - 3y^2 is a quadratic form in the variables and . The coefficients usually belong to a ...

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 In mathematics, for given real numbers ''a'' and ''b'', the logarithm log''b'' ''a'' is a number ''x'' such that . Analogously, in any group ''G'', powers ''b'k'' can be defined for all integers ''k'', and the discrete logarithm log''b' ...

of a number

Statistics

Index (statistics) In statistics and research design, an index is a composite statistic – a measure of changes in a representative group of individual data points, or in other words, a compound measure that aggregates multiple indicators. Indexes – also known as ...

, 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 semiotics, linguistics, anthropology, and philosophy of language, indexicality is the phenomenon of a ''sign'' pointing to (or ''indexing'') some object in the context in which it occurs. A sign that signifies indexically is called an index or, ...

, 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