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

Plan a stop in bustling Cebu City to visit the Basilica Minore del Santo Niño de Cebu and Magellan’s Cross Pavilion—cultural cornerstones that paved the way to the propagation of Christianity as the country’s most dominant religion. —Condé Nast Traveler, 28 Mar. 2026

The Sky are not pursuing this option currently — their goal is to retain Atkins as a cornerstone of the 2026 roster — but the loss of this trade alternative would be a blow nonetheless. —Julia Poe, Chicago Tribune, 27 Mar. 2026

The Higgs is the cornerstone of our physics models, dictating the mass of all other particles. —Mariangela Lisanti, Twin Cities, 27 Mar. 2026

This is what monopolization, and really the cornerstone of antitrust cases, are all about. —Dana Taylor, USA Today, 27 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