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

Examples of keystone in a Sentence

Tourism is the city's economic keystone. the keystone of his faith
Recent Examples on the Web Ohio’s role in national politics was as a keystone, a place balanced delicately between Democrats and Republicans, organized labor and small-business people, cities and rural areas. The New Yorker, 16 Apr. 2022 For a personal touch, window grilles and a keystone feature the monogram of the previous owners, the family behind JOB-brand cigarette papers. Kelsey Mulvey, ELLE Decor, 10 May 2022 Your brand consists of multiple pieces, but video should be considered the keystone of it all. John Hall, Forbes, 8 May 2022 Perhaps, Barbour muses, science could eventually leverage keystone genes for protecting and restoring biodiversity. Anna Funk, Scientific American, 31 Mar. 2022 Scientists now know that predators are keystone species—ones on which entire ecosystems depend. Rachel Nuwer, Scientific American, 28 Apr. 2022 In addition to sloping sandy hills and long stretches of pristine beach, this 184-acre park is perfect for spotting the gopher tortoise, a keystone species that's found only in the southeastern United States. Jared Ranahan, Travel + Leisure, 30 Mar. 2022 This year's bill, triple the size of the 2015 measure, is a keystone of President Joe Biden's push to create jobs and build out the nation's roads, water systems, broadband coverage and other projects. Arkansas Online, 12 Nov. 2021 Vaccination status will be the keystone of the Canadian and Mexican border reopening, which will happen in two steps. Rachel Chang, Condé Nast Traveler, 13 Oct. 2021 See More

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.

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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Dictionary Entries Near keystone

key station


keystone effect

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Last Updated

25 May 2022

Cite this Entry

“Keystone.” Dictionary, Merriam-Webster, Accessed 25 May. 2022.

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More Definitions for keystone


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

More from Merriam-Webster on keystone

Nglish: Translation of keystone for Spanish Speakers Encyclopedia article about keystone


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