: 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
Tourism is the city's economic keystone. the keystone of his faith
Recent Examples on the WebThe department did not respond to requests for comment about funding for the new positions, but in a budget proposal to the California Legislature the agency called beavers an important keystone species that could be used to combat climate change. Nathan Solis, Los Angeles Times, 7 Sep. 2022 In their view, both the mammoth and thylacine were keystone species in their respective ecosystems, which have been out of balance as a result of their loss. John Timmer, Ars Technica, 16 Aug. 2022 As a keystone species, sea otters help preserve our ever-important kelp forests by controlling the sea urchin population. Matt Pawlik, Los Angeles Times, 4 Aug. 2022 An economic powerhouse, Taiwan is also a keystone of the electronics supply chain and perhaps the world’s most important source of advanced microchips. Paul Mozur, BostonGlobe.com, 2 Aug. 2022 As the heir of both the House of Tudor and the House of York, Arthur was a keystone in Henry VII's plan to maintain peace in the kingdom and prevent rival factions from rising against his claim to the throne. Lauren Hubbard, Town & Country, 24 May 2022 And the concept is quite provocative, since Demna has been such a keystone of the hype machine, with his Triple S sneakers and zillion-layer jackets and LOL-ish T-shirts. Rachel Tashjian, Harper's BAZAAR, 23 May 2022 Coyotes are often called a keystone species, which means their presence has a significant and positive impact on the natural environment. John Laidler, BostonGlobe.com, 12 May 2022 The research performed on his converted 126-foot Bering Sea crab vessel, OCEARCH, is helping to unlock the life history puzzle of great white sharks and other keystone species essential for the health of the oceans. Kirby Adams, The Courier-Journal, 12 May 2022 See More