from
The Collaborative International Dictionary of English v.0.48
Pontoon \Pon*toon"\, n. [F. ponton (cf. It. pontone), from L.
ponto, -onis, fr. pons, pontis, a bridge, perhaps originally,
a way, path: cf. Gr. ? path, Skr. path, pathi, panthan. Cf.
{Punt} a boat.]
1. (Mil.) 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.
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2. (Naut.) 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.
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{Pontoon bridge}, a bridge formed with pontoons.
{Pontoon train}, the carriages of the pontoons, and the
materials they carry for making a pontoon bridge.
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Note: The French spelling ponton often appears in scientific
works, but pontoon is more common form.
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from
The Collaborative International Dictionary of English v.0.48
Bridge \Bridge\ (br[i^]j), n. [OE. brig, brigge, brug, brugge,
AS. brycg, bricg; akin to Fries. bregge, D. brug, OHG.
brucca, G. br["u]cke, Icel. bryggja pier, bridge, Sw. brygga,
Dan. brygge, and prob. Icel. br[=u] bridge, Sw. & Dan. bro
bridge, pavement, and possibly to E. brow.]
1. A structure, usually of wood, stone, brick, or iron,
erected over a river or other water course, or over a
chasm, railroad, etc., to make a passageway from one bank
to the other.
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2. Anything supported at the ends, which serves to keep some
other thing from resting upon the object spanned, as in
engraving, watchmaking, etc., or which forms a platform or
staging over which something passes or is conveyed.
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3. (Mus.) The small arch or bar at right angles to the
strings of a violin, guitar, etc., serving of raise them
and transmit their vibrations to the body of the
instrument.
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4. (Elec.) A device to measure the resistance of a wire or
other conductor forming part of an electric circuit.
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5. A low wall or vertical partition in the fire chamber of a
furnace, for deflecting flame, etc.; -- usually called a
{bridge wall}.
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{Aqueduct bridge}. See {Aqueduct}.
{Asses' bridge}, {Bascule bridge}, {Bateau bridge}. See under
{Ass}, {Bascule}, {Bateau}.
{Bridge of a steamer} (Naut.), a narrow platform across the
deck, above the rail, for the convenience of the officer
in charge of the ship; in paddlewheel vessels it connects
the paddle boxes.
{Bridge of the nose}, the upper, bony part of the nose.
{Cantalever bridge}. See under {Cantalever}.
{Draw bridge}. See {Drawbridge}.
{Flying bridge}, a temporary bridge suspended or floating, as
for the passage of armies; also, a floating structure
connected by a cable with an anchor or pier up stream, and
made to pass from bank to bank by the action of the
current or other means.
{Girder bridge} or {Truss bridge}, a bridge formed by
girders, or by trusses resting upon abutments or piers.
{Lattice bridge}, a bridge formed by lattice girders.
{Pontoon bridge}, {Ponton bridge}. See under {Pontoon}.
{Skew bridge}, a bridge built obliquely from bank to bank, as
sometimes required in railway engineering.
{Suspension bridge}. See under {Suspension}.
{Trestle bridge}, a bridge formed of a series of short,
simple girders resting on trestles.
{Tubular bridge}, a bridge in the form of a hollow trunk or
rectangular tube, with cellular walls made of iron plates
riveted together, as the Britannia bridge over the Menai
Strait, and the Victoria bridge at Montreal.
{Wheatstone's bridge} (Elec.), a device for the measurement
of resistances, so called because the balance between the
resistances to be measured is indicated by the absence of
a current in a certain wire forming a bridge or connection
between two points of the apparatus; -- invented by Sir
Charles Wheatstone.
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