keystone

noun

key·​stone ˈkē-ˌstōn 

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

Synonyms

• base
• basis
• bedrock
• bottom
• cornerstone
• footing
• foundation
• ground
• groundwork
• root
• underpinning
• warp
• warp and woof

Examples of keystone in a Sentence

Tourism is the city's economic keystone.

the keystone of his faith

Recent Examples on the Web

Baobabs can live for more than 1,000 years, acting as the keystone species in dry forest environments in Madagascar, a swathe of continental Africa, and northwest Australia. —Tom Page, CNN, 24 June 2024

The weekly podcast, however, has given him a platform to continue building his following, while remaining a keystone voice in Trump's movement. —Karissa Waddick, USA TODAY, 18 June 2024

Enlarge / Nvidia's CEO Jensen Huang delivers his keystone speech ahead of Computex 2024 in Taipei on June 2, 2024. —Benj Edwards, Ars Technica, 3 June 2024

The Gala, which falls on the first Monday of May, purportedly celebrates the Anna Wintour Costume Center’s keystone exhibit every year. —Constance Grady, Vox, 7 May 2024

Word History

First Known Use

circa 1637, in the meaning defined at sense 1

Phrases Containing keystone

• keystone species

Kids Definition

keystone

noun

key·​stone ˈkē-ˌstōn 

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