[ key-suhn, -son ]
See synonyms for caisson on
  1. 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.

  2. a boatlike structure used as a gate for a dock or the like.

  1. Nautical.

    • 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.

    • a watertight structure built against a damaged area of a hull to render the hull watertight; cofferdam.

  2. a two-wheeled wagon, used for carrying artillery ammunition.

  3. an ammunition chest.

  4. a wooden chest containing bombs or explosives, used formerly as a mine.

  5. Architecture. coffer (def. 4).

Origin of caisson

1695–1705; <French, Middle French <Old Provençal, equivalent to caissa box (see case2) + -on augmentative suffix

Other words from caisson

  • caissoned, adjective

Words Nearby caisson Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use caisson in a sentence

  • The horses became entangled among the ropes, and stumbled over the gun and caisson, throwing their riders to the earth.

    In Hostile Red | Joseph Altsheler

British Dictionary definitions for caisson


/ (kəˈsuːn, ˈkeɪsən) /

  1. a watertight chamber open at the bottom and containing air under pressure, used to carry out construction work under water

  2. a similar unpressurized chamber

  1. a watertight float filled with air, used to raise sunken ships: See also camel (def. 2)

  2. a watertight structure placed across the entrance of a basin, dry dock, etc, to exclude water from it

    • a box containing explosives, formerly used as a mine

    • an ammunition chest

    • a two-wheeled vehicle containing an ammunition chest

  3. another name for coffer (def. 3)

Origin of caisson

C18: from French, assimilated to caisse case ²

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