Definition of: quoin

(koin, kwoin) noun
1. A large square ashlar or stone at the angle of a wall.
2. An external angle of a building.
3. A vertical, angular, ornamental projection from a wall face.
4. A wedge-shaped stone of an arch.
5. A block cut obliquely at the bottom to support a vertical column or pilaster on an inclined plane.
6. An internal angle, as of a room; a corner.
7. A wedge, or wedgelike piece.
8. Printing A wedge, or pair of wedges, by which to lock up type in a chase or galley.
—v.t. To fasten or provide with a quoin or quoins. [Var. of COIN]
QUOINS
A. Printer's metal quoins.
a. Single quoin.
b. Pair of quoins ready for locking with key.
B. Quoins of dressed stone.