(1):

(n.) A flat fold; a doubling, as of cloth; a pleat; as, a box plait.

(2):

(n.) A braid, as of hair or straw; a plat.

(3):

(v. t.) To fold; to double in narrow folds; to pleat; as, to plait a ruffle.

(4):

(v. t.) To interweave the strands or locks of; to braid; to plat; as, to plait hair; to plait rope.