PONTOON

pontoon

(noun) a float supporting a seaplane

pontoon

(noun) (nautical) a floating structure (as a flat-bottomed boat) that serves as a dock or to support a bridge

Source: WordNet® 3.1

Etymology 1

Noun

pontoon (plural pontoons)

(military) A flat-bottomed boat used as a support for a temporary bridge.

A floating structure supporting a bridge or dock.

Synonym: pontoon bridge

A box used to raise a sunken vessel.

A float of a seaplane.

A lighter or barge used for loading or unloading ships.

Etymology 2

Noun

pontoon (uncountable)

(card games) A card game in which the object is to obtain cards whose value adds up to, or nearly to, 21 but not exceed it.

Synonym: vingt-et-un

Source: Wiktionary

Pon*toon", n. Etym: [F. ponton (cf. It. pontone), from L. ponto, - onis, fr. pons, pontis, a bridge, perhaps originally, a way, path: cf. Gr. path, pathi, panthan. Cf. Punt a boat.]

1. (Mil.)

Definition: 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.

2. (Naut.)

Definition: 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. Pontoon bridge, a bridge formed with pontoons.

– Pontoon train, the carriages of the pontoons, and the materials they carry for making a pontoon bridge.

Note: The French spelling ponton often appears in scientific works, but pontoon is more common form.

Source: Webster’s Unabridged Dictionary 1913 Edition