Quoin

1. (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.
2. (n.) A wedgelike piece of stone, wood metal, or other material, used for various purposes
3. (n.) to support and steady a stone.
4. (n.) To support the breech of a cannon.
5. (n.) To wedge or lock up a form within a chase.
6. (n.) To prevent casks from rolling.