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

Nearly 30 years later, J&D Interiors remains a cornerstone of the North Side business community, and a testament to the remarkable life of a remarkable woman. —Richard J. Gonzales, Fort Worth Star-Telegram, 29 Nov. 2025

Porches are such a cornerstone of the holidays, in fact, that more and more people are hiring professional designers to kit them out for the season. —Miranda Crowell, Better Homes & Gardens, 29 Nov. 2025

Their historic rivalries, iconic parquet floor, and enduring commitment to excellence make the Celtics a cornerstone of basketball history and one of the most respected teams in sports. —Ben Verbrugge, MSNBC Newsweek, 28 Nov. 2025

That is something that’s been a cornerstone for me for forever. —Ct Jones, Rolling Stone, 28 Nov. 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