1911 Encyclopædia Britannica/Cleat

CLEAT (a word common in various forms to many Teutonic languages, in the sense of a wedge or lump, cf. “clod” and “clot”), a wedge-shaped piece of wood fastened to ships’ masts and elsewhere to prevent a rope, collar or the like from slipping, or to act as a step; more particularly a piece of wood or metal with double or single horns used for belaying ropes. A “cleat” is also a wedge fastened to a ship’s side to catch the shores in a launching cradle or dry dock. “Cleat” is also used in mining for the vertical cleavage-planes of coal.