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Keystone

[KEE-stohn]

Part of speech: noun

Origin: English, 17th century

1.

A central stone at the summit of an arch, locking the whole together.

2.

The central principle or part of a policy, system, etc., on which all else depends.

Examples of Keystone in a sentence

"The last year’s monthly profits were the keystone of the CEO’s argument for a new sales approach."

"The health of some species, such as elephants, is considered the keystone of an entire ecosystem."

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About Keystone

“Keystone” is an architectural and building term formed in English by fusing the noun “key,” meaning both an object to open and close a lock and also a crucial step, with the noun “stone.”

Did you Know?

In order to complete the building of a stone arch, traditional masons place a final stone at the peak of the arch to connect all the other pieces while redistributing their weight. This is called a “keystone,” both because it is crucial to the integrity of the structure, and because without it, the arch cannot be locked together. Without a keystone, a traditional stone arch will collapse under its own weight. In modern English, a “keystone” refers to any central idea or value upon which other things are based. For example, fighting climate change is a keystone of most environmental policies.

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