keystone

noun

key·​stone ˈkē-ˌstōn How to pronounce keystone (audio)
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 ethicL. 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The auto focus and keystone correction make setup effortless. Shubham Yewale, PC Magazine, 16 May 2025 He’s mostly played second base this year with a little third base mixed in, profiling better at the keystone. Keith Law, New York Times, 29 Apr. 2025 In short, the necessary ingredients of all-in AI innovation won’t be enmeshed in the AI Continent keystones, which, regrettably, ultimately the restraints and limits on AI will undermine the upbeat and rosy aspirations accordingly. Lance Eliot, Forbes.com, 14 Apr. 2025 Shasta Lake, the state’s largest reservoir and the keystone of the federal Central Valley Project, stood at 94% of capacity on Friday, holding 116% of its historical average. Sharon Bernstein, Sacbee.com, 11 Apr. 2025 See All Example Sentences for keystone

Word History

First Known Use

circa 1637, in the meaning defined at sense 1

Time Traveler
The first known use of keystone was circa 1637

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Cite this Entry

“Keystone.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/keystone. Accessed 29 May. 2025.

Kids Definition

keystone

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

More from Merriam-Webster on keystone

Last Updated: - Updated example sentences
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