View source for Index

{{for|Wikipedia’s index|Wikipedia:Index|selfref=y}}
{{wiktionary|Index|index|indexes|indice|indices}}
'''Index''' ({{plural form}}: '''indexes''' or '''indices''') may refer to:
{{tocright}}

==Arts, entertainment, and media==
===Fictional entities===
* [[Index (A Certain Magical Index)|Index (''A Certain Magical Index'')]], the titular character of 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)|''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

==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]], 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 [[sigma notation|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|''n''th root]]
* Index of a [[linear map#Index|linear map]], the dimension of the map's kernel minus the dimension of its cokernel
* Index of a [[Matrix (mathematics)|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

==See also==
* [[Indexer (disambiguation)]]
* {{Look from}}
* {{In title}}

{{disambiguation|geo}}