Quoin

(n.) Originally, a solid exterior angle, as of a building; now, commonly, one of the selected pieces of material by which the corner is marked.

Quoin - Other Definitions

(n.) Originally, a solid exterior angle, as of a building; now, commonly, one of the selected pieces of material by which the corner is marked.
(n.) A wedgelike piece of stone, wood metal, or other material, used for various purposes
(n.) to support and steady a stone.
(n.) To support the breech of a cannon.
(n.) To wedge or lock up a form within a chase.
(n.) To prevent casks from rolling.