cornerstone

American  

[kawr-ner-stohn] / ˈkɔr nərˌstoʊn /

noun

• cornerstones
  plural

1. a stone uniting two masonry walls at an intersection.

2. a stone representing the nominal starting place in the construction of a monumental building, usually carved with the date and laid with appropriate ceremonies.

3. something that is essential, indispensable, or basic.

   The cornerstone of democratic government is a free press.

4. the chief foundation on which something is constructed or developed.

   The cornerstone of his argument was that all people are created equal.

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cornerstone British  

/ ˈkɔːnəˌstəʊn /

noun

1. a stone at the corner of a wall, uniting two intersecting walls; quoin

2. a stone placed at the corner of a building during a ceremony to mark the start of construction

3. a person or thing of prime importance; basis

   the cornerstone of the whole argument

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Other Word Forms

Noun Inflected Forms

• cornerstones
  plural

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Etymology

Origin of cornerstone

Middle English word dating back to 1250–1300; see origin at corner, stone

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Explanation

A cornerstone is literally a stone at the corner of a building. It’s an important stone, so it also means “the basic part of something,” as in, the cornerstone of the suffragette movement was getting women the right to vote. When a building goes up, putting in the cornerstone is a big deal and people celebrate. Many cornerstones are engraved with historical information about the building, such as the year the building was built. The cornerstone is sometimes made of a different material from the rest of the building too. From the sense of "foundation," cornerstone also means "essential element.” If you’re really into Italian food, you might say that pasta is the cornerstone of your diet.

Example Sentences

See Examples For:

cornerstone cornerstones

“Ride safety is a cornerstone of our business, and when we see guest confidence affected, we take it seriously.”

From Los Angeles Times ● Oct. 13, 2026

The near-crash has halted flights between the U.A.E. and Israel, a cornerstone of the two countries reaching a diplomatic recognition deal in 2020.

From The Wall Street Journal ● Oct. 9, 2026

France along with Germany is the cornerstone of the euro area, and the euro is the only other reserve currency in the world after the dollar, he noted.

From MarketWatch ● Oct. 1, 2026

Announcing the closure on Tuesday, , external Six Flags Magic Mountain Park President Brian Oerding said: "Ride safety is a cornerstone of our business, and when we see guest confidence affected, we take it seriously."

From BBC ● Sep. 29, 2026

With architecture and construction such a fascination in Chicago, cornerstone ceremonies became extravagant affairs.

From "The Devil in the White City" by Erik Larson

As tech has grown as an overwhelming force in our lives, the visual design cornerstones associated with it—arial font, minimalist branding, bright colors and clean lines—have become the norm.

From Slate ● Aug. 21, 2026

This devotion to authenticity is one of Thompson’s cornerstones.

From Salon ● May 15, 2026

Arteta's side have been criticised throughout the season for their style of play with their strengths being their threat from set-pieces and their excellence in defending the cornerstones.

From BBC ● Apr. 19, 2026

After the loss to the Knicks, Boston said so long to three former All-Stars and cornerstones of their title-winning roster.

From The Wall Street Journal ● Jan. 28, 2026

The foundations of both were nearly finished and awaited the installation of cornerstones.

From "The Devil in the White City" by Erik Larson

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Related Words

• essential
• foundation
• keystone
• linchpin
• mainstay
• pillar

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