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

Walker, like Norris himself, was half-Cherokee and half-Irish, a cornerstone of both the character and the actor’s backstory. —Emily St. Martin, Los Angeles Times, 20 Mar. 2026

This property is crucial for generating quantum entanglement between distant nodes, another cornerstone of future quantum communication networks, as per the release. —Prabhat Ranjan Mishra, Interesting Engineering, 19 Mar. 2026

Once visited by emperors seeking clarity and samurai tending to battle wounds, these onsen remain cornerstones of Japanese culture. —Kelsey Eisen, Robb Report, 19 Mar. 2026

The proof is considered a cornerstone of arithmetic geometry, the field that studies curves and shapes represented by these types of equations. —Joseph Howlett, Scientific American, 19 Mar. 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