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

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

"I want my kids to say, 'Mom worked really hard for something very important,' because it is very important. It's the cornerstone of our country," she said.

From Barron's ● Oct. 5, 2026

Roy has made renter protections a cornerstone of her campaign and says it will be key to stemming the city’s homeless crisis.

From Los Angeles Times ● Oct. 1, 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

Indeed, I can say I am in agreement with those who say that the ability to draw up a good staff plan is the cornerstone of any decent butler's skills.

From "The Remains of the Day" by Kazuo Ishiguro

Spiritual jazz and psychedelic soul are cornerstones of her sound, along with new-age accouterments like prayer bowls and chimes blended with instruments including Fender Rhodes keyboards and vibraphone.

From The Wall Street Journal ● Sep. 1, 2026

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

The King spelt out the cornerstones: there had to be support for Nato, "keeping North Americans and Europeans safe from our common adversaries".

From BBC ● Apr. 28, 2026

The cornerstones of this country’s operation are economic and political strength and power.

From "The Autobiography of Malcolm X" by Alex Malcolm X;Hailey

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Related Words

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

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