- quoin⇄noun 1. an outside angle or corner of a wall or building.
2. a stone forming an outside angle of a wall; cornerstone.
3. a wedge-shaped block of wood, metal, or stone, used in building, especially one of the stones in the curve of an arch. - quoin⇄quoin, noun, verb.
- quoin⇄v.t. 1. to provide or construct with quoins.
2. to secure or raise with quoins.