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 initiative, expected to cost about $28 billion through 2029, is a cornerstone of Prabowo’s administration and one of his key campaign promises. — ABC News, 5 Sep. 2026

And as time went on, the barn that was once the cornerstone of farm life slowly began deteriorating beyond repair, leading the farm to undergo another major change this year in an effort to restore the barn’s former liveliness. — Jenna Ebbers, Kansas City Star, 4 Sep. 2026

Yet another is to convey that getting your child vaccinated is the cornerstone of modern medicine and the best advice a pediatrician can give. — Eric Boodman, STAT, 3 Sep. 2026

The practice of pulling over random vehicles, often based on little more than a hunch, has been a cornerstone of the city’s crime-fighting strategy for decades. — Hailey Wang, Los Angeles Times, 1 Sep. 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