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 Sandringham Christmas walk has long been a cornerstone of the royal holiday season, drawing crowds of well-wishers eager to catch a glimpse of the family. —Erin Hill, PEOPLE, 25 Dec. 2025

The book, one of the cornerstone texts about the identify of Palestinians in Israel, is a tragic and satiric story of Saeed, a Palestinian who becomes a citizen of Israel. —Irene Nasser, CNN Money, 25 Dec. 2025

The Leaf just got a major redesign and appears to be a cornerstone of Nissan's new brand international strategy. —Charles Singh, Nashville Tennessean, 22 Dec. 2025

The Sabbath goes back thousands of years and is a cornerstone of Western civilization. —Judith Shulevitz, The Atlantic, 22 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