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

Other cornerstones of the week, such as Louis Vuitton, Junya Watanabe and Comme des Garçons, will take up their usual times on the schedule. —Lily Templeton, Footwear News, 18 Dec. 2025

As a person, family man, and driver, his accomplishments helped form a cornerstone of our organization. —CBS News, 18 Dec. 2025

Key cornerstone investors included Fidelity, UBS, Chinese investment firm CDH Investments and Cithara Fund amongst others. —Lee Ying Shan, CNBC, 17 Dec. 2025

Raime were early cornerstones of Blackest Ever Black, a goth-hearted label that had cast a seductive shadow over the 2010s underground, but the duo had recently pivoted to weightless grime. —Philip Sherburne, Pitchfork, 16 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