A pontoon is a floating platform, often one used to support a bridge.
...a pontoon bridge.
pontoon in British English1
(pɒnˈtuːn)
noun
1.
a.
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
b.
(as modifier)
a pontoon bridge
2. nautical
a float, often inflatable, for raising a vessel in the water
Word origin
C17: from French ponton, from Latin pontō punt, floating bridge, from pōns bridge
pontoon in British English2
(pɒnˈtuːn)
noun
1. Also called: (esp US) 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 or her first two cards
Word origin
C20: probably an alteration of French vingt-et-un, literally: twenty-one
pontoon in American English
(pɑnˈtun)
noun
1.
a flat-bottomed boat
2.
any of a number of these, or of some other floating objects, as hollow cylinders, used as supports for a temporary bridge (pontoon bridge)
3.
a float on an aircraft
Also ; US ˈponton (pɑntən)
Word origin
Fr ponton < L ponto < pons (gen. pontis), a bridge: see pons
Examples of 'pontoon' in a sentence
pontoon
There was a motor cruiser moored at the end of the pontoon, dazzlingly white with a blue band above the watermark.
Higgins, Jack CONFESSIONAL (2002)
And then I saw it -- the high, white bow of that fishing cruiser gliding in towards the end of the pontoon.
Innes, Hammond HIGH STAND (2002)
`Wait till we raft some Panzers over, wait till we get a pontoon bridge!
Townsend, Eileen IN LOVE AND WAR (2002)
Iker and Broker edged through the open hatch and balanced on the pontoon as the plane maneuvered toward shore.