copestone

American  

[kohp-stohn] / ˈkoʊpˌstoʊn /

noun

1. the top stone of a building or other structure.

2. a stone used for or in coping.

3. the crown or completion; finishing touch.

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copestone British  

/ ˈkəʊpˌstəʊn /

noun

1. Also called: coping stone.  a stone used to form a coping

2. Also called: capstone.  the stone at the top of a building, wall, etc

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Etymology

Origin of copestone

First recorded in 1560–70; cope ² + stone