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

By the 1980s, England was beginning its turn away from churchgoing as a cornerstone of society, so nothing as extroverted or nakedly clerical as gospel choirs would fit a downcast, monochromatic land anyhow. — Gabriel Szatan, Pitchfork, 18 Oct. 2026

The Spurs believe the most imposing version of their defensive cornerstone has yet to arrive. — Jeff McDonald, San Antonio Express-News, 16 Oct. 2026

Since its introduction, hydroxyurea has become a cornerstone of sickle cell disease treatment that has helped thousands successfully manage their condition. — Steven Ross Johnson, CNBC, 16 Oct. 2026

Talarico has made populist economic messaging a cornerstone of his campaign, and his economic plan includes measures like increasing taxes for the wealthiest Americans. — Casey Murray, Houston Chronicle, 16 Oct. 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