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 question is whether the Bucks feel this is the time to let their longtime franchise cornerstone go, amid a disappointing season and with Antetokounmpo likely to be sidelined for the next several weeks with another instance of a calf injury. —Tim Reynolds, Baltimore Sun, 30 Jan. 2026

And what will happen to the independent film industry if its cornerstone festival loses its footing? —Amy Nicholson, Los Angeles Times, 30 Jan. 2026

And InterContinental Dominica Cabrits Resort & Spa, set in Cabrits National Park, has become a cornerstone for luxury travelers who want comfort without disconnecting from nature. —Laura Begley Bloom, Forbes.com, 29 Jan. 2026

Minaj has sparked backlash for her approving regard of the president, who has made violent persecution of immigrants a cornerstone of his domestic policy since taking office last January. —Ryan Coleman, Entertainment Weekly, 29 Jan. 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