(1):

(v.) Something which reenforces or strengthens.

(2):

(v.) (b) An additional thickness of canvas, cloth, or the like, around an eyelet, buttonhole, etc.

(3):

(v.) That part of a cannon near the breech which is thicker than the rest of the piece, so as better to resist the force of the exploding powder. See Illust. of Cannon.

(4):

(v. t.) To strengthen with new force, assistance, material, or support; as, to reenforce an argument; to reenforce a garment; especially, to strengthen with additional troops, as an army or a fort, or with additional ships, as a fleet.