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

On the other hand, vehicle stops – which are widely considered to be one of the most dangerous law enforcement activities – have always been a cornerstone for local police, which are trained extensively on how to appropriately conduct them. — Nicki Brown, CNN Money, 18 July 2026

Statins block some of the liver’s production of cholesterol and are the cornerstone of treatment. — Matthew Perrone, Fortune, 16 July 2026

Founded in 1944 by Jimmie and Minnie McKee, the Excelsior Club was once a cornerstone of Black culture in Charlotte. — Claire Harutunian, Charlotte Observer, 16 July 2026

And a starting rotation containing two cornerstones who have shown up for a total of eight games. — Los Angeles Times, 16 July 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