key·​stone | \ ˈkē-ˌstōn How to pronounce keystone (audio) \

Definition of keystone

1 : the wedge-shaped piece at the crown of an arch that locks the other pieces in place — see arch illustration
2 : something on which associated things depend for support determination, a keystone of the puritan ethic— L. S. Lewis
3 or keystone species : a species of plant or animal that produces a major impact (as by predation) on its ecosystem and is considered essential to maintaining optimum ecosystem function or structure

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Examples of keystone in a Sentence

Tourism is the city's economic keystone. the keystone of his faith
Recent Examples on the Web Beavers, a keystone species, have been found to help mitigate the spread of wildfires, thanks to their water-damming habits. Lucy Sherriff, oregonlive, "Oregon tribes reintroduce beavers to the Beaver State, but hurdles remain," 1 May 2021 App Tracking Transparency is one of the keystone features in iOS 14.5 and one that Apple is rightly talking up. David Phelan, Forbes, "Apple Releases Hard-Hitting Message Warning Against iPhone Data Tracking," 27 Apr. 2021 In that sense, the frame is both the bedrock and keystone of the entire Chief selection. Bryan Campbell, Robb Report, "First Ride: How the 2022 Indian Chief Line Redefines the Production Cruiser," 21 Apr. 2021 But Peters’s story — and the keystone of Blanding’s campaign — has another layer to it. Washington Post, "Her unlikely campaign for governor began at a gravesite in Virginia," 26 Apr. 2021 Remember, knowing exactly how much money your daughter will owe each month is the keystone to making a good decision, not whether or not the government enacts a student loan forgiveness program. Peter Dunn, USA TODAY, "Should you go for the more expensive college in case student loans are forgiven? Don't bank on it.," 20 May 2020 Atlanta, for example, is a hip-hop keystone known as the home of trap music, but new waves of talent, as disparate as J.I.D and Playboi Carti, are experimenting with mood and content. Mankaprr Conteh, Rolling Stone, "Kenny Mason Raps as Well as He Rocks," 15 Apr. 2021 Beavers are considered a keystone species that helps the overall health of stream ecosystems, so the reintroduction plan was carried out by the federal Bureau of Land Management with the involvement of Arizona’s Game and Fish Department. Ian James, The Arizona Republic, "'It's so cool to see': Building dams by night, beavers resurface along Arizona's San Pedro River," 9 Apr. 2021 Today, the walking memoir — in which the main character chronicles his amblings, making mundane observations and grandiose discoveries along the way — is a significant subgenre, with Kazin’s book as its keystone work. Washington Post, "Alfred Kazin’s “A Walker in the City” charts an intellectual awakening, block by block," 4 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'keystone.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of keystone

circa 1637, in the meaning defined at sense 1

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Time Traveler for keystone

Time Traveler

The first known use of keystone was circa 1637

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Statistics for keystone

Last Updated

13 May 2021

Cite this Entry

“Keystone.” Dictionary, Merriam-Webster, Accessed 17 May. 2021.

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More Definitions for keystone



English Language Learners Definition of keystone

: a large stone at the top of an arch that locks the other stones in place
: something on which other things depend for support


key·​stone | \ ˈkē-ˌstōn How to pronounce keystone (audio) \

Kids Definition of keystone

1 : the wedge-shaped piece at the top of an arch that locks the other pieces in place
2 : something on which other things depend for support

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