Quoin

1.

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.

A wedgelike piece of stone, wood metal, or other material, used for various purposes

1.

To support and steady a stone.

2.

To support the breech of a cannon.

3.

To wedge or lock up a form within a chase.

4.

To prevent casks from rolling.