Definition

1. Noun:
   • A floating structure: A pontoon is a hollow, airtight structure, often cylindrical or box-shaped, that provides buoyancy. It can be a single unit or one of several used to support something on water.
   • A floating support for a bridge or dock: In this context, a pontoon is a flat-bottomed boat or a similar floating platform used as a foundational support for a temporary bridge (pontoon bridge) or a floating dock.
   • A float for a seaplane: A pontoon is one of the buoyant, boat-like structures attached to the underside of a seaplane, enabling it to land on and take off from water.

Usage and Examples

• Noun:
  • The old dock was built on wooden pontoons. (The old dock was supported by floating structures.)
  • Engineers deployed pontoons to quickly construct a bridge across the river. (Engineers used floating platforms to build the bridge.)
  • The seaplane's pontoons skimmed the surface of the lake during landing. (The seaplane's floats touched the lake's surface.)

Advanced Usage

• "Pontoon bridge": A temporary bridge supported by floating pontoons.
  • The military built a pontoon bridge for the troops to cross.
• In card games (chiefly British English), "pontoon" is a variant of the game "twenty-one" or blackjack. (Note: This is a distinct meaning from the floating structure.)

Variants and Related Words

• Pontoon bridge (n): A bridge that rests on floating pontoons.
• Pontoon boat (n): A flat-bottomed boat that relies on pontoons for buoyancy.

Synonyms

• Float: A buoyant object or structure.
• Buoy: A anchored float serving as a navigation mark or support.
• Barge: A flat-bottomed boat for carrying freight, sometimes used as a support platform (similar function).

Related Phrases and Compounds

• Lay pontoons: The action of placing or assembling pontoons to form a bridge or platform.
  • The unit's task was to lay pontoons across the canal.

Noun

1. a float supporting a seaplane
2. (nautical) a floating structure (as a flat-bottomed boat) that serves as a dock or to support a bridge