Keystone

How to spell keystone

8 letters · 2 syllables

How to pronounce keystone

Say the part in capitals loudest.

What does keystone mean?

1. nounThe central or most essential part on which everything else depends.
2. nounThe wedge-shaped stone set at the top of an arch that locks the other stones in place.

Keystone in a sentence

• Affordable housing was the keystone of the council's new policy.

• The mason eased the final keystone into the crown of the stone arch.

• Trust is the keystone of any lasting business partnership.

• A carved date marks the keystone above the old bridge.

Where does keystone come from?

Language of origin: Germanic

Keystone is a transparent English compound, formed by joining 'key' and 'stone'. The first element comes from the Old English 'caeg', a word for the metal implement that locks and unlocks; over time 'key' also took on the broader sense of the one thing that holds a system together or makes it work. The second element is the Old English 'stan', the ancestor of modern 'stone'. The word arose as an architectural term during the seventeenth century to name the wedge-shaped block set at the very top of an arch, the piece that locks all the other stones in place so the structure cannot collapse. Because that single block carries such structural importance, 'keystone' quickly took on a figurative life meaning the central, indispensable part of any larger whole. Spelling it is straightforward once you see it as two familiar words glued together, with the silent 'e' of 'stone' kept intact.

How the word is built

• key (the central, locking element)
• stone (a shaped block of rock)