quoin >> /k(w)ɔɪn/
Definition: [transitive verb] Provide (a wall) with quoins or corners.
Example: the white plaster walls quoined with red sandstone blocks
Definition: [transitive verb] Lock up (a form) with a quoin.
Definition: [noun] An external angle of a wall or building.
Example: smaller stations followed the same pattern; stone-built, with strongly accented quoins
Definition: [noun] A wedge or expanding mechanical device used for locking a letterpress form into a chase.
Definition: [noun] A wedge for raising the level of a gun barrel or for keeping it from rolling.