keystone

[ kee-stohn ]

noun

1. the wedge-shaped piece at the summit of an arch, regarded as holding the other pieces in place.
2. something on which associated things depend:

   the keystone of one's philosophy.

   Synonyms: linchpin, foundation, principle, basis

3. Also called keystone sack. Baseball Slang. second base ( def 1 ).

keystone

/ ˈkiːˌstəʊn /

noun

1. Also calledheadstonequoin the central stone at the top of an arch or the top stone of a dome or vault
2. something that is necessary to connect or support a number of other related things

Word History and Origins

Origin of keystone¹

First recorded in 1630–40; key ¹ + stone

Example Sentences

Regardless, Musk and Ramaswamy are forging ahead with hires, using language that suggests their project is the keystone of Trump's second term's agenda.

From Salon

Many keystone tree species of the region, including red and white oaks, depend on fire to curb undergrowth and create space within the canopy so sunlight can reach seedlings.

From Salon

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.

From Los Angeles Times

The rule of law’s keystone is our judicial system.

From Salon

Martin Luther King Jr. Community Hospital is the keystone of Los Angeles County’s effort to meet the needs of a population struggling with poverty and poor health.

From Los Angeles Times

Related Words

• base
• cornerstone
• foundation
• fundament