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

Becoming a father made the show appealing for creative reasons too, when Grimes met with Hudnut and learned that the relationship between Kayce and Tate would be a cornerstone of the series. —Jim Hemphill, IndieWire, 24 May 2026

Both players are being relied upon to be cornerstones of the franchise, and both showed promise in their rookie seasons. —Ryan Canfield Outkick, FOXNews.com, 23 May 2026

Just down the road, Dock’s Oyster House is the city’s seafood cornerstone. —Jessica Chapel, Condé Nast Traveler, 23 May 2026

Estonia is targeting a threefold expansion of its film industry within five years, with two new sound stages under construction forming the cornerstone of a bid to become a full-service hub for international productions, officials said at the Cannes Film Festival. —Naman Ramachandran, Variety, 22 May 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