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[key-suh n, -son] /ˈkeɪ sən, -sɒn/
a structure used in underwater work, consisting of an airtight chamber, open at the bottom and containing air under sufficient pressure to exclude the water.
a boatlike structure used as a gate for a dock or the like.
  1. Also called camel, pontoon. a float for raising a sunken vessel, sunk beside the vessel, made fast to it, and then pumped out to make it buoyant.
  2. a watertight structure built against a damaged area of a hull to render the hull watertight; cofferdam.
a two-wheeled wagon, used for carrying artillery ammunition.
an ammunition chest.
a wooden chest containing bombs or explosives, used formerly as a mine.
Architecture, coffer (def 4).
Origin of caisson
1695-1705; < French, Middle French < Old Provençal, equivalent to caissa box (see case2) + -on augmentative suffix
Related forms
caissoned, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for caisson
  • To make an oil-collecting caisson, such a pile would be used as a collar around a funnel-topped tube that would sit over the leak.
  • Once the entire crowd was in place, the pallbearers came to attention and began to remove the casket from the caisson.
  • Also, the timber member at the northwest caisson or cylinder pier was badly decayed.
  • caisson repair work would include the installation of a caisson support floor and of a new seaward-facing wall.
  • Anchors were installed on the bay bottom and cables from the anchors were used to guide the caisson into place.
  • The subsea caisson remnants are comprised of concrete and re-enforcing steel that was previously removed down to solid concrete.
  • Within the enclosed caisson, sediments can be mixed and treatment reagents can be added.
  • Atop the caisson sits a pump house with an intake pipe extending down into the caisson.
  • Upon completion of painting of a caisson the contractor may apply for payment for that element.
  • One gun and caisson with limbers, made up a platoon under a sergeant and two corporals.
British Dictionary definitions for caisson


/kəˈsuːn; ˈkeɪsən/
a watertight chamber open at the bottom and containing air under pressure, used to carry out construction work under water
a similar unpressurized chamber
a watertight float filled with air, used to raise sunken ships See also camel (sense 2)
a watertight structure placed across the entrance of a basin, dry dock, etc, to exclude water from it
  1. a box containing explosives, formerly used as a mine
  2. an ammunition chest
  3. a two-wheeled vehicle containing an ammunition chest
another name for coffer (sense 3)
Word Origin
C18: from French, assimilated to caissecase²
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for caisson

1704, from French caisson "ammunition wagon, box, crate," from Middle French caisson "large box" (16c.), from Italian cassone, augmentative form of cassa "a chest," from Latin capsa "a box" (see case (n.2)).

Online Etymology Dictionary, © 2010 Douglas Harper
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