quoin

In architecture, both the external corner of a building and, more often, one of the stones used to form that corner. These stones are both structural and decorative in that they often differ in jointing, colour, texture, or size from the masonry of the adjoining walls. Usually quoins are toothed (i.e., set in short courses in a regular pattern of alternating lengths). Such construction dates back to ancient Rome.

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• Quoin (architecture), the corner stones that anchor the edge of the building wall
• In printing, quoins are wedges used by printers to hold the hand-set type in place in a printer's chase
• In naval warfare, a quoin was a wedge manipulated at the breech end of a cannon to raise or lower the barrel