pontoon

¹ American  

[pon-toon] / pɒnˈtun /

Also ponton

noun

1. Military. a boat or some other floating structure used as one of the supports for a temporary bridge over a river.

2. a float for a derrick, landing stage, etc.

3. Nautical. a float for raising a sunken or deeply laden vessel in the water; a camel or caisson.

4. a seaplane float.

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pontoon ² American  

[pon-toon] / pɒnˈtun /

noun

British.

1. the card game twenty-one.

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pontoon ¹ British  

/ pɒnˈtuːn /

noun

1. 1. a watertight float or vessel used where buoyancy is required in water, as in supporting a bridge, in salvage work, or where a temporary or mobile structure is required in military operations

   2. ( as modifier )

      a pontoon bridge

2. nautical a float, often inflatable, for raising a vessel in the water

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pontoon ² British  

/ pɒnˈtuːn /

noun

1. Also called: twenty-one.   vingt-et-un.  a gambling game in which players try to obtain card combinations worth 21 points

2. (in this game) the combination of an ace with a ten or court card when dealt to a player as his first two cards

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Etymology

Origin of pontoon¹

1585–95; < French ponton < Latin pontōn- (stem of pontō ) flat-bottomed boat, punt

Origin of pontoon²

1915–20; alteration of French vingt-et-un twenty-one

Explanation

A pontoon is a flat boat that floats with the help of hollow tubes, also called pontoons. A lakeside resort might have pontoons and canoes that you can rent for the day. The feature that distinguishes a pontoon, or pontoon boat, is the use of airtight cylinders to keep it buoyant. You can call these structures pontoons or floats, and they're used for things like houseboats, and some seaplanes that can land on water — and float there, thanks to pontoons. Sometimes pontoons are also used to support bridges and docks. The word stems from the Latin pontonem, "flat-bottomed boat," and its root pons, or "bridge."

Example Sentences

The last time, it was a Soviet-made pontoon bridge.

From The Wall Street Journal • Apr. 1, 2026

Rescue teams from Thursday used earth moving equipment on a pontoon to dredge a channel through the sand to allow the animal to escape.

From Barron's • Mar. 27, 2026

The icy water is like fire on my skin and all my brain can think of is making it to the pontoon without needing help from the lifeguards.

From BBC • Feb. 8, 2025

Meanwhile, he used the deposit money to bankroll expensive purchases, authorities say, including a yacht, a pontoon boat, two Mercedes-Benz automobiles, two Ford pickup trucks, a recreation vehicle, a tractor, three ATVs and fishing equipment.

From Los Angeles Times • Aug. 24, 2024

The dressing station was on the Austrian side of the river under the edge of the hill and stretcher-bearers would bring the wounded back across the pontoon bridge.

From "A Farewell To Arms" by Ernest Hemingway