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 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

media

• Indexed, a Web cartoon by
• Index, album by

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

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
• Webserver 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

uses

• satellite
• Life
• skyscraper