index

[ in-deks ]

/ ˈɪn dɛks /

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See synonyms for: index / indexed / indices on Thesaurus.com

noun, plural in·dex·es, in·di·ces

[in-duh-seez]. /ˈɪn dəˌsiz/.

(in a nonfiction book, monograph, etc.) a more or less detailed alphabetical listing of names, places, and topics along with the numbers of the pages on which they are mentioned or discussed, usually included in or constituting the back matter.

a sequential arrangement of material, especially in alphabetical or numerical order.

something used or serving to point out; a sign, token, or indication: a true index of his character.

something that directs attention to some fact, condition, etc.; a guiding principle.

a pointer or indicator in a scientific instrument.

a piece of wood, metal, or the like, serving as a pointer or indicator.

Digital Technology.

a value that identifies and is used to locate a particular element within a data array or table.
a reference table that contains the keys or references needed to address data items.
the part of a search engine where website addresses are cataloged with their associated keywords in order to quickly retrieve the most relevant web pages when a user submits a search query.

Also called fist, hand .Printing. a sign in the shape of a hand with extended index finger, used to point out a particular note, paragraph, etc.

a light, smooth cardboard stock.

the forefinger.

a number or formula expressing some property, ratio, etc., of something indicated: index of growth; index of intelligence.

Statistics. index number.

Economics. price index.

Algebra.

an exponent.
the integer n in a radical  defining the n-th root: ∛ is a radical having index three.
a subscript or superscript indicating the position of an object in a series of similar objects, as the subscripts 1, 2, and 3 in the series x1, x2, x3.
winding number.

Horology. a leverlike regulator for a hairspring.

(initial capital letter)Roman Catholic Church.

(usually initial capital letter) any list of forbidden or otherwise restricted material deemed morally or politically harmful by authorities: an Index of disapproved books relating to Communism.

Optics. index of refraction.

Obsolete.

a table of contents.
a preface or prologue.

verb (used with object)

to provide with an index, as a book.

to enter in an index, as a name or topic.

to serve to indicate: warm breezes indexing the approach of spring.

to place (a book) on an official list as politically or morally harmful: The commissar insisted on indexing the book.

to rotate (work) on a milling machine in order to repeat the milling operation at a new position.

Economics. to adjust (wages, taxes, etc.) automatically according to changes in the cost-of-living level or another economic indicator, especially to offset inflation.

Digital Technology. (of a search engine) to catalog (a website) using keywords: Search engines use automated algorithms to index billions of web pages, but that still accounts for only a fraction of the content on the internet.

QUIZ

THINGAMABOB OR THINGUMMY: CAN YOU DISTINGUISH BETWEEN THE US AND UK TERMS IN THIS QUIZ?

Do you know the difference between everyday US and UK terminology? Test yourself with this quiz on words that differ across the Atlantic.

Question 1 of 7

In the UK, COTTON CANDY is more commonly known as…

candystring

candyfloss

candypuff

TAKE THE QUIZ TO FIND OUT

Origin of index

First recorded in 1350–1400; Middle English, from Latin: “informer, pointer,” equivalent to in-in-² + -dec- (combining form of dic-, “show, declare, indicate,” akin to teach;see indicate) + -s nominative singular ending;

OTHER WORDS FROM index

in·dex·a·ble, adjectivein·dex·er, nounin·dex·i·cal, adjectivein·dex·i·cal·ly, adverb

in·dex·less, adjectivenon·in·dexed, adjectiveo·ver·in·dex, verb (used with object)o·ver·in·dex·ing, nounre·in·dex, verb (used with object)un·in·dexed, adjectivewell-indexed, adjective

WORDS THAT MAY BE CONFUSED WITH index

appendix, index , supplement

Words nearby index

indeterminate equation, indeterminate sentence, indeterminate vowel, indetermination, indeterminism, index, indexation, index card, index case, index crime, Index Expurgatorius

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use index in a sentence

The changes won’t disrupt the level of the index, the company says.
Salesforce, Amgen, and Honeywell Int’l will join Dow Jones Industrial Average|Andrew Nusca|August 24, 2020|Fortune
In its updated 2020 wildfire mitigation plan, SDG&E said it developed a vegetation risk index, which could help identify where it needs to do the 25-foot pruning.
Watchdog Warns: SDG&E’s Tree-Trimming Plan Could Worsen Wildfires|MacKenzie Elmer|August 24, 2020|Voice of San Diego
SAC spun the index off into a separate company in 2019 to further develop the technology behind it, and is promoting its adoption by other industries.
A greener and more compassionate apparel industry|Tate Ryan-Mosley|August 19, 2020|MIT Technology Review
On those two previous occasions, value beat the index by the biggest margin.
The champ’s big comeback: Why beaten-down value stocks are poised to thrive|Shawn Tully|August 18, 2020|Fortune

By contrast, health care—the second-largest sector—carries a market cap of just under $4 trillion and represents only 14% of the index.
‘It’s clicks versus bricks’: Why tech stocks won’t be fading anytime soon|reymashayekhi|August 17, 2020|Fortune
A helpful pictorial index provides photographs of the actual objects.
The Best Coffee Table Books of 2014|Robert Birnbaum|December 13, 2014|DAILY BEAST
There is an expanded place-name index with more than 150,000 entries, and separate undersea, Moon, and Mars features.
The Best Coffee Table Books of 2014|Robert Birnbaum|December 13, 2014|DAILY BEAST
He stuck his index finger in the red welt around the spot where bin Laden shot me.
I Shot Bin Laden|Elliot Ackerman|November 16, 2014|DAILY BEAST
The country was ranked 144 of 177 nations surveyed by Transparency International in its 2013 graft perception index.
Corruption Eats Away at Ukraine Military|Charles McPhedran|October 21, 2014|DAILY BEAST
He soon invents the “Efram Daniels Expulsion Index (EDEI) … a hybrid futures and prediction market.”
In a New Novel, Apathetic Teenagers Usher in the Apocalypse|Elliot Ackerman|June 9, 2014|DAILY BEAST
The degree of pallor furnishes a rough index to the amount of hemoglobin in the corpuscle.
A Manual of Clinical Diagnosis|James Campbell Todd
Wright and his followers regard the opsonic index as an index of the power of the body to combat bacterial invasion.
A Manual of Clinical Diagnosis|James Campbell Todd
A low color-index probably indicates a mild type of the disease.
A Manual of Clinical Diagnosis|James Campbell Todd
The color-index is thus almost invariably low, the average being about 0.5.
A Manual of Clinical Diagnosis|James Campbell Todd
The changes in hemoglobin and red cells resemble those of a moderate symptomatic anemia, with rather low color-index.
A Manual of Clinical Diagnosis|James Campbell Todd

British Dictionary definitions for index

index

/ (ˈɪndɛks) /

noun plural -dexes or -dices (-dɪˌsiːz)

an alphabetical list of persons, places, subjects, etc, mentioned in the text of a printed work, usually at the back, and indicating where in the work they are referred to

See thumb index

library science a systematic list of book titles or author's names, giving cross-references and the location of each book; catalogue

an indication, sign, or token

a pointer, needle, or other indicator, as on an instrument

maths

another name for exponent (def. 4)
a number or variable placed as a superscript to the left of a radical sign indicating by its value the root to be extracted, as in ³√8 = 2
a subscript or superscript to the right of a variable to express a set of variables, as in using x i for x 1, x 2, x 3, etc

a numerical scale by means of which variables, such as levels of the cost of living, can be compared with each other or with some base number

a number or ratio indicating a specific characteristic, property, etcrefractive index

Also called: fist a printer's mark (☛) used to indicate notes, paragraphs, etc

obsolete a table of contents or preface

verb (tr)

to put an index in (a book)

to enter (a word, item, etc) in an index

to point out; indicate

to index-link

to move (a machine or a workpiece held in a machine tool) so that one particular operation will be repeated at certain defined intervals

Derived forms of index

indexer, nounindexless, adjective

Word Origin for index

C16: from Latin: pointer, hence forefinger, title, index, from indicāre to disclose, show; see indicate

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Cultural definitions for index

index

An alphabetical list of subjects treated in a book. It usually appears at the end of the book and identifies page numbers on which information about each subject appears.

index

Origin of index

OTHER WORDS FROM index

WORDS THAT MAY BE CONFUSED WITH index

Words nearby index

Words related to index

How to use index in a sentence

British Dictionary definitions for index

Derived forms of index

Word Origin for index

Cultural definitions for index