index

1 of 2

noun

in·​dex ˈin-ˌdeks How to pronounce index (audio)
plural indexes or indices ˈin-də-ˌsēz How to pronounce index (audio)
1
: a list (as of bibliographical information or citations to a body of literature) arranged usually in alphabetical order of some specified datum (such as author, subject, or keyword): such as
a
: a list of items (such as topics or names) treated in a printed work that gives for each item the page number where it may be found
b
: a list of publicly traded companies and their stock prices
c
: a bibliographical analysis of groups of publications that is usually published periodically
2
a
: a number (such as a ratio) derived from a series of observations and used as an indicator or measure
specifically : index number
b
: the ratio of one dimension of a thing (such as an anatomical structure) to another dimension
3
a
: a device (such as the pointer on a scale or the gnomon of a sundial) that serves to indicate a value or quantity
b
: something (such as a physical feature or a mode of expression) that leads one to a particular fact or conclusion : indication
4
plural usually indices : a number or symbol or expression (such as an exponent) associated with another to indicate a mathematical operation to be performed or to indicate use or position in an arrangement
3 is the index of the expression {latex}\sqrt[3]{5}{/latex} to indicate the cube root of 5
5
: a character ☞ used to direct attention to a note or paragraph

called also fist

6
: a list of restricted or prohibited material
specifically, Index : a formerly published list of books the reading of which was prohibited or restricted for Roman Catholics by the church authorities

index

2 of 2

verb

indexed; indexing; indexes

transitive verb

1
a
: to provide with an index
b
: to list in an index
all persons and places mentioned are carefully indexed
2
: to serve as an index of
3
: to regulate (wages, prices, interest rates, etc.) by indexation

intransitive verb

: to index something
indexer noun

Examples of index in a Sentence

Noun Look up the recipe for potato soup in the index. Potato soup is listed under “soup” in the index. The card catalog is an index to the materials in the library. the index on a scale Verb This search engine has indexed hundreds of millions of websites. indexed all the books in the library by category See More
Recent Examples on the Web
Noun
Another tool to consider is a sophisticated search engine that will index the data based on its content and allow administrators to query the resulting index to identify the most relevant content. Russ Kennedy, Forbes, 21 Feb. 2024 That is why the index is so heavily dominated by technology stocks today. Nicole Goodkind, CNN, 21 Feb. 2024 Kristin Smith, a public finance researcher with the nonprofit Headwaters Economics, helped create a rural capacity index that measures how prepared communities are to navigate the labyrinth of federal grant applications. USA TODAY, 20 Feb. 2024 The source: My trusty spreadsheet reviewed the California Association of Realtors’ year-end affordability indexes, which combine pricing, incomes, and mortgage rates to track the financial challenge of acquiring a residence. Jonathan Lansner, San Diego Union-Tribune, 18 Feb. 2024 Umaña points out that both lightweight acetate and high index plastic have been used by luxury eyeglass manufacturers for years to make comfortably light, impact-resistant eyewear. Boone Ashworth, WIRED, 16 Feb. 2024 Nvidia, which has been riding a mania around artificial-intelligence technology, rose 2.5% Wednesday and was the single strongest force pushing up the S&P 500 index. Stan Choe, Fortune, 15 Feb. 2024 The other factor to consider is the bulb’s CRI (or color rendering index), which Pelle recommends at 90 or above. Caitie Kelly Gisela Williams Julekha Dash Catherine Hong Devorah Lev-Tov, New York Times, 15 Feb. 2024 Nvidia shares have been on a tear since 2023, when investors swept up in AI hype bought up shares of Big Tech stocks, spurring a bull market against a backdrop of sky-high interest rates and leading the S&P 500 index to jump 24% last year. Cnn.com Wire Service, The Mercury News, 15 Feb. 2024
Verb
This process starts with the adoption of a modern IT setup in which data is de-siloed, meticulously indexed, and made visible so that advanced analytics can glean actionable insights at speed. Fabrice Haiat, Forbes, 23 Feb. 2024 Google uses them to crawl and index the entire web for its search engine, which has become the interface to the web and brings the company billions of dollars a year. Peter Rubin, Longreads, 15 Feb. 2024 The deal would index the child tax credit to inflation for the first time, so most parents would benefit from a boost of about $100 on their tax returns in 2025. Jeff Stein, Washington Post, 1 Feb. 2024 In 2025, Part D out-of-pocket drug costs will be capped at $2,000, an amount that will be indexed to the growth rate in Part D costs. Byrichard Eisenberg, Fortune Well, 25 Oct. 2023 Because the legislation President George H.W. Bush signed at the time did not index it to inflation, alcohol tax rates actually dropped a whopping 36% in the years to 2017. Cara Poland, STAT, 20 Dec. 2023 The Tax Cuts and Jobs Act of 2017 boosted the standard deduction at the time from $6,500 for singles to $12,000 and from $13,000 to $24,000 for married couples, with the amounts indexed for inflation. The Arizona Republic, 10 Jan. 2024 In Minnesota, Democratic Gov. Tim Walz signed a law that indexes the gas tax to inflation as well as imposes a 50-cent fee on deliveries valued at more than $100. Tribune News Service, Hartford Courant, 7 Jan. 2024 Google has agreed to pay 100 million Canadian dollars, equivalent to $73.6 million, indexed to inflation, into a fund, said Canada’s Heritage Minister Pascale St-Onge. Vipal Monga, WSJ, 29 Nov. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'index.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Noun

Latin indic-, index, from indicare to indicate

First Known Use

Noun

1561, in the meaning defined at sense 3a

Verb

1720, in the meaning defined at transitive sense 1a

Time Traveler
The first known use of index was in 1561

Dictionary Entries Near index

Cite this Entry

“Index.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/index. Accessed 3 Mar. 2024.

Kids Definition

index

1 of 2 noun
in·​dex ˈin-ˌdeks How to pronounce index (audio)
plural indexes
-ˌdek-səz
or indices -də-ˌsēz How to pronounce index (audio)
1
a
: a device (as the pointer on a scale) used to indicate a value or quantity
b
: something that leads a person to a particular fact or conclusion : indication
the price of goods is an index of the economy
2
: an alphabetical list in a printed work that gives with each item listed the page number where it may be found
3
plural usually indices : a mathematical figure, letter, or expression (as the exponent 3 in a3) showing a power or root of another
4
: a symbol ☞ used to direct attention

index

2 of 2 verb
1
a
: to provide with an index
index a book
b
: to list in an index
2
: to serve as an index of
indexer noun

Medical Definition

index

noun
in·​dex ˈin-ˌdeks How to pronounce index (audio)
plural indexes or indices -də-ˌsēz How to pronounce index (audio)
1
2
: a list (as of bibliographical information or citations to a body of literature) arranged usually in alphabetical order of some specified datum (as author, subject, or keyword)
Index Medicus of the United States National Library of Medicine
3
a
: a ratio or other number derived from a series of observations and used as an indicator or measure (as of a condition, property, or phenomenon)
physiochemical indexes of the urine, the blood, and the gastric juiceJournal of the American Medical Association
b
: the ratio of one dimension of a thing (as an anatomical structure) to another dimension see cephalic index, cranial index

Legal Definition

index

1 of 2 noun
in·​dex
: a numerical measure or indicator (as of inflation or economic performance) see also consumer price index

index

2 of 2 transitive verb
: to link (as wages, rates, or investments) to an index
under the contract wages were indexed to inflation

More from Merriam-Webster on index

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