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

The Dodgers’ franchise cornerstone was dealing with swelling on the back of his left knee during Thursday’s game against the Pittsburgh Pirates, which prompted Roberts to remove him from the game and ensure that the issue did not escalate. —Fabian Ardaya, New York Times, 13 June 2026

Club Café has long been a cornerstone of the LGBTQ community in Boston. —Todd Plummer, Condé Nast Traveler, 12 June 2026

Getty Images The Philadelphia Phillies have seen plenty of former players continue their careers in independent leagues and overseas after leaving Major League Baseball, but one former cornerstone has now hit an unexpected turning point. —Peter Chawaga, Forbes.com, 12 June 2026

Historically Black colleges and universities have long understood that community is a cornerstone of opportunity. —Albert D. Mosley, The Orlando Sentinel, 12 June 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