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

Real estate is an asset class that is especially well-suited to the 100-year plan and has become a cornerstone of many family office portfolios. —Belinda G. Schwartz, Fortune, 7 Mar. 2026

There’s no doubt that the Angels’ Zach Neto is talented and a cornerstone for the team to build around. —Los Angeles Times, 7 Mar. 2026

Ultimately, the scene becomes the cautionary cornerstone of a sea change in Byron’s world. —Hunter Ingram, Variety, 5 Mar. 2026

The Everlane Double-Knit Half-Zip Pullover will undoubtedly serve as a cornerstone of your spring outfit rotation. —Kyra Surgent, InStyle, 4 Mar. 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