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 cornerstone of her vision was a Steven Meisel photo shoot, published in the March 2006 issue of Vogue Italia. —Leah Dolan, CNN Money, 5 Dec. 2025

With decades of legacy, strong brand recognition, and a deep connection to generations of fans, Topps remains a cornerstone of the trading card world. —Ben Verbrugge, MSNBC Newsweek, 5 Dec. 2025

In Boulder, Thompson said, the school district considers communication and education cornerstones of safety. —Tribune News Service, San Diego Union-Tribune, 3 Dec. 2025

Since then, more than 30 Air Jordan silhouettes have been released, becoming a cornerstone of Jordan’s billion-dollar fortune. —Samantha Stutsman, PEOPLE, 3 Dec. 2025

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