To incline or droop the head forward with a short, quick, involuntary motion, as when drowsy or sleepy; specifically, in botany, to droop or curve downward by a short bend in the peduncle: said of flowers. See nodding, p. a.Figuratively, to be guilty of a lapse or inadvertence, as when nodding with drowsiness.To salute, beckon, or express assent by a slight, quick inclination of the head.To bend or incline the top or part corresponding to the head with a quick jerky motion, simulating the nodding of a drowsy person.To incline or bend, as the head or top.To signify by a nod: as, to nod assent.To affect by a nod or nods in a manner expressed by a word or words connected: as, to nod one out of the room; to nod one's head off.n. A short, quick, forward and downward motion of the head, either voluntary, as when used as a familiar salutation, a sign of assent or approbation, or given as a signal, command, etc., or involuntary, as when one is drowsy or sleepy.n. A quick forward or downward inclination of the upper part or top of anything.