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.

---

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

---

Other Word Forms

Noun Inflected Forms

• cornerstones
  plural

Etymology

Origin of cornerstone

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

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

Pubs, a quintessential cornerstone of British communities, are closing at the rate of around one a day, according to the British Beer and Pub Association.

From Barron's ● Jul. 23, 2026

Freezing rents was a cornerstone of his plans to put money back in New Yorkers’ pockets.

From The Wall Street Journal ● Jul. 22, 2026

This is not just one part of American history but a cornerstone of it.

From Slate ● Jul. 20, 2026

"They are a cornerstone of our laws to protect children from content they should not be seeing."

From BBC ● Jul. 9, 2026

The idea had been conceived in Lusaka by Oliver and the ANC, and the campaign was the cornerstone of a new strategy that would put our cause in the forefront of people’s minds.

From "Long Walk to Freedom" by Nelson Mandela

One of the cornerstones of Fifa's World Cup disciplinary process is that you cannot appeal.

From BBC ● Jul. 5, 2026

Homeownership is one of the cornerstones of the American dream, deeply ingrained in our culture as a symbol of financial success and stability.

From MarketWatch ● Apr. 24, 2026

The Green Bay Packers were formed a year later, and the two institutions, about five miles apart, grew up side by side as cornerstones of the community.

From Salon ● Mar. 10, 2026

Carney has made boosting commerce with Europe and Asia cornerstones of his strategy to backstop Canada's economy, should free trade with Washington collapse.

From Barron's ● Feb. 26, 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

Related Words

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