Originally: any of various lengths of rope stretched taut between different parts of a ship to prevent tangling or fouling, as to deflect rigging from anchors, windlasses, etc. Later also: any labour-saving device or contrivance; (more vaguely) a gadget, a thingummy. Chiefly historical in recent use.

Chiefly in form timmynoggy. In some Cornish sailing ships before the middle of the 19th century: a notched piece of wood into which the end of a spar may be fitted.