BALLOON, or BALON, in a general sense, signifies any spherical hollow body, of whatever matter it be composed, or for whatever purposes it be designed. Thus, with chemists, balloon denotes a round short-necked vessel, used to receive what is distilled by means of fire; in architecture, a round globe on the top of a pillar; and among engineers, a kind of bomb made of pasteboard, and played off in fire-works, either in the air or on the water, in imitation of a real bomb.