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

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

It was the latest jolt to South Korea’s confidence in an alliance that has formed a cornerstone of Washington’s defense strategy in Asia since the end of World War II.

From Los Angeles Times ● Aug. 19, 2026

Either the franchise views the player as a cornerstone and pays him at an upper-echelon rate, or it moves on.

From The Wall Street Journal ● Aug. 10, 2026

It was also a cornerstone investor in SK Hynix’s recent U.S. debut.

From MarketWatch ● Jul. 31, 2026

Empathy, on stage, becomes a cornerstone of experiencing live performance that pulls heartstrings, inspires raucous laughter or elicits a collective groan when a poorly-hatched plan falters.

From Salon ● Jul. 30, 2026

“In the next few weeks, I will be speaking with all of you and showing you how this building, Pipo Place, will be the cornerstone and future of this community!”

From "The Epic Fail of Arturo Zamora" by Pablo Cartaya

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

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 books are cornerstones of Krasznahorkai’s Nobel-winning oeuvre, and the films are two of the defining movies of their era and established Tarr as a giant of cinema.

From Los Angeles Times ● Jan. 8, 2026

I was suddenly pointedly aware of the fact that I was standing in one of the cornerstones of civilization, talking to the Master Archivist of the University.

From "The Name of the Wind" by Patrick Rothfuss

Related Words

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