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 strategy is anchored in creating a fil rouge between each property with common codes of its banner. — Sofia Celeste, Footwear News, 5 Oct. 2026

Young enough to hold ambition but ripe enough that a teenage cornerstone like Caleb Wilson might listen. — Joel Lorenzi, New York Times, 3 Oct. 2026

But the long-running political struggle over the cornerstone law continues apace, with both sides now turning their full attention from the Capitol to the voters. — Andrew Graham, Sacbee.com, 30 Sep. 2026

The Chicago Tribune Editorial Board’s tradition of making political endorsements is a cornerstone of this newspaper’s history. — The Editorial Board, Chicago Tribune, 28 Sep. 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