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

Optical zoom and vertical lens shift, along with autofocus, keystone correction, screen fit and obstacle avoidance, also help make positioning and setup a breeze. —New Atlas, 10 Oct. 2024

Catch up quick: The U.S. Supreme Court ruled in a bribery case involving a former Portage, Indiana, mayor that there is a difference between a bribe and a gratuity, essentially nixing a keystone corruption law for the federal government. —Justin Kaufmann, Axios, 9 July 2024

As a Times report detailed earlier this year, Combs has long packaged himself as an outlaw made good — his keystone company is called Bad Boy Entertainment, after all. —Mary McNamara, Los Angeles Times, 18 Sep. 2024

Partners View all partners Email X (Twitter) Facebook LinkedIn Print With less than two months until Election Day, Pennsylvania has emerged as the keystone state in each party’s plan to win the White House. —Alauna Safarpour, The Conversation, 18 Sep. 2024

Word History

First Known Use

circa 1637, in the meaning defined at sense 1

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