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

His hefty price tag — a record for a British player at the time — reflects City’s faith that Anderson can help replace Rodri, for so long the cornerstone of Pep Guardiola’s team, and help them back to the summit of the Premier League. — Cerys Jones, New York Times, 22 Aug. 2026

Southern Miss transfer Chris Jones is the cornerstone of a group that will also lean on Omar Graham, Blake Nichelson and Mikai Gbayor for consistency on a squad that ranked 10th in rushing defense in the ACC last year. — Andre C. Fernandez, Miami Herald, 19 Aug. 2026

In the months that followed, the Mets bid farewell to franchise cornerstones Pete Alonso, Brandon Nimmo, Jeff McNeil and — despite trying to retain him — closer Edwin Diaz. — Peter Sblendorio, New York Daily News, 19 Aug. 2026

In 15 seasons with the Royals, the captain and franchise cornerstone has seen just about every stage of team building. — Kansas City Star, 18 Aug. 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