Noun

Singular index

Plural indexes or indices

index (plural indexes or indices)

1. An alphabetical listing of items and their location; for example, the index of a book lists words or expressions and the pages of the book upon which they are to be found.
2. (linguistics) A type of noun where the meaning of the form changes with respect to the context. E.g., 'Today's newspaper' is an indexical form since its referent will differ depending on the context. See also icon and symbol.
3. The index finger, the forefinger.
4. A sign; an indication; a token.

   His son's empty guffaws ... struck him with pain as the indices of a weak mind.

5. (programming) A positive or non-negative integer indicating the location of data within a vector or vector based multidimensional array.
6. (computing) A key indicating the location of data or an object, e.g. within a database table, associative array, or hash table.
7. (computing, databases) A data structure that improves the performance of operations on a table.
8. (economics) a single number calculated from an array of prices or of quantities.

Synonyms

• (index finger): arrow-finger
• (index finger): demonstrator
• (index finger): forefinger
• (index finger): index finger
• (index finger): insignitor
• (index finger): lickpot
• (index finger): pointling
• (index finger): showing finger
• (index finger): teacher
• inventory
• See also Wikisaurus:index finger

Derived terms

• index term
• indexical
• indexless
• price index
• refractive index

Related terms

• indicate
• indicator
• indication
• indicia

An index is a system used to make finding information easier.

Index may also refer to:

• Index (publishing), a detailed list, usually arranged alphabetically, of the specific information in a publication
• Index cards in a rolodex or old library card catalog, early and mid 20th century technologies for maintaining such lists
• Index (mathematics), for various meanings of the word in mathematics
• Index (economics), a single number calculated from an array of prices and quantities
  • Price index, a typical price for some good or service
  • Operating Index, a tool to compare the operating performance of a company with its peer universe
• Index, Washington, a town in Snohomish County, Washington, United States
• Index, New York, a hamlet in the County and Town of Otsego, New York, United States
• Index (typography), a largely obsolete punctuation mark
• Indexing (motion), a kind of motion in many areas of mechanical engineering and machining

Publications:

• Index Librorum Prohibitorum, a list of publications which the Catholic Church censored
• Germany's List of Media Harmful to Young People, colloquially known as The Index, published by the Bundesprüfstelle für jugendgefährdende Medien
• Index Magazine, was a prominent New York City based publication for art and culture
• Truman State University Index, the weekly student newspaper
• The Index, the student newspaper of Kalamazoo College, published since 1877
• The Index (journal), a European propaganda journal created by Henry Hotze to support the Confederate States of America during the American Civil War
• index.hu, a prominent news and community portal in Hungarian
• Toaru Majutsu no Index, a Japanese light novel, manga, and anime series

In computers and information retrieval:

• Index (database), a feature in a computerized database which allows quick access to the rows in a table
• Index (information technology), either an integer which identifies an array element, or a data structure which enables fast lookup
• Index (search engine), for supporting information retrieval in search engines
• Webserver directory index, a default or index web page in a directory on a web server, such as index.html
• Subject indexing, describing the content of a document by keywords
• BitTorrent index, a list of .torrent files available for searches

Other:

• The Index, an item on the Halo (megastructure) in the Halo series of video games
• The Index (Dubai), a tower under construction in Dubai
• Index (retailer), a defunct UK catalogue retailer formerly owned by the Littlewoods group and known as Littlewoods Index
• Index finger, the second digit of a human hand
• Index fund, a collective investment scheme
• Indexicality, in linguistics, the variation of meaning of an utterance according to certain features of the context in which it is uttered