keystone

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noun key·stone \ˈkē-ˌstōn\

Definition of keystone

  1. 1 :  the wedge-shaped piece at the crown of an arch that locks the other pieces in place — see arch illustration

  2. 2 :  something on which associated things depend for support determination, a keystone of the puritan ethic — L. S. Lewis

  3. 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

  1. Tourism is the city's economic keystone.

  2. the keystone of his faith

Recent Examples of keystone from the Web

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

Other Architecture Terms


KEYSTONE Defined for English Language Learners

keystone

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noun

Definition of keystone for English Language Learners

  • : a large stone at the top of an arch that locks the other stones in place

  • : something on which other things depend for support


KEYSTONE Defined for Kids

keystone

play
noun key·stone \ˈkē-ˌstōn\

Definition of keystone for Students

  1. 1 :  the wedge-shaped piece at the top of an arch that locks the other pieces in place

  2. 2 :  something on which other things depend for support



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