Pontoon

·noun A wooden flat-bottomed boat, a metallic cylinder, or a frame covered with canvas, India rubber, ·etc., forming a portable float, used in building bridges quickly for the passage of troops.

II. Pontoon ·noun A low, flat vessel, resembling a barge, furnished with cranes, capstans, and other machinery, used in careening ships, raising weights, drawing piles, ·etc., chiefly in the Mediterranean; a lighter.