cornerstone

noun

cor·​ner·​stone ˈkȯr-nər-ˌstōn 

1

: a stone forming a part of a corner or angle in a wall

specifically : such a stone laid at a formal ceremony

2

: a basic element : foundation

a cornerstone of foreign policy

Synonyms of cornerstone

• basis
• foundation
• bedrock

Examples of cornerstone in a Sentence

Officials held a ceremony to lay the cornerstone for a new library.

Trust is the cornerstone of their relationship.

Recent Examples on the Web

For Tamarac firefighter Freddy Matos, now 23 years into his career, the day remains a cornerstone of his service. — Joan Murray, CBS News, 12 Sep. 2026

In fact, sports fans in general were baffled that Dončić would be teaming up with LeBron James out west, while the Mavericks traded away their franchise cornerstone. — Scott Thompson Outkick, FOXNews.com, 11 Sep. 2026

Released 20 years ago this week, the horror novel by Max Brooks quickly became one of the undisputed cornerstones of walking dead canon. — Andrew Paul, Popular Science, 10 Sep. 2026

The City of Los Angeles has long recognized that water conservation is the cornerstone of multiple strategies to improve water supply reliability for its residents. — Sarah Viramontes, Los Angeles Times, 9 Sep. 2026

Word History

First Known Use

13th century, in the meaning defined at sense 1

Rhymes for cornerstone

• acetone
• anglophone
• baritone
• bourguignon
• buspirone
• chaperon
• chaperone
• cobblestone
• collarbone
• cortisone
• dictaphone
• dithizone

Kids Definition

cornerstone

noun

cor·​ner·​stone ˈkȯr-nər-ˌstōn 

1

: a stone forming part of a corner in a wall

2

: something of basic importance

the cornerstone of our foreign policy