Definition of caisson in English:


Pronunciation /ˈkeɪs(ə)n//kəˈsuːn/


  • 1A large watertight chamber, open at the bottom, from which the water is kept out by air pressure and in which construction work may be carried out under water.

    • ‘The 25-m - long x 10-m-wide caissons travelled on pontoons before being sunk into place.’
    • ‘The housing consists of prefabricated concrete caissons which are inset in the lagoon floor and contain service tunnels and machinery.’
    • ‘The buttresses rise from caisson caps, each covering six concrete caissons.’
    • ‘Some 30 million ft of lumber and 1 million steel reinforcing rods supported the original Wacker Drive, with about 600 caissons excavated to an average of 95 ft.’
    • ‘Rebar cages for the caissons were assembled remotely, moved on-site, and lowered into the hole at night; the hole was filled with concrete, leaving a cold joint at the top of the apron.’
    • ‘These were noticed first among men in new industrial applications: tunnelling below water and working in caissons.’
    • ‘It's a combined highway and transit construction project and requires drilling foundation caissons in areas with underground utilities.’
    • ‘The seal course at the bottom of the caissons is 8 m thick and required about 6,000 m³ of underwater concrete.’
    • ‘The caisson has been constructed inside a ‘cofferdam’ - a box-like structure built of pilings and a concrete floor.’
    • ‘Concrete grade beams spanning between the caissons were used to accommodate external envelope conditions and elevator pits.’
    • ‘The caissons were huge hollow reinforced concrete blocks that were floated across the channel and then sunk when in position.’
    1. 1.1 A floating vessel or watertight structure used as a gate across the entrance of a dry dock or basin.
      • ‘These floats transported the great floating concrete caissons which formed the sea walls of the Mulberry Harbours.’
      • ‘Constructed of various concrete caissons and pontoons, the Mulberrys were the innovation that made the Normandy campaign following the D-Day landings possible.’
      • ‘The port consisted of a series of caissons forming the outside wall, with various pontoons and jetties inside, mainly following the design of a bailey bridge (big meccano).’
      • ‘A massive 7,000-tonne concrete caisson has replaced the temporary steel coffer dam, and three cranes - one of ten tonnes, two of 25 tonnes - were transported across Five Basin to Nine Dock by floating crane.’
      • ‘He sailed to the raid in HMS Campbeltown and landed by jumping over the ship's bow onto the caisson to conduct demolition work ashore.’
  • 2historical A chest or wagon for holding or conveying ammunition.

    • ‘We saw the bronze of a Civil War general on horseback, soldiers hanging onto an artillery caisson clattering to his side.’
    • ‘It has also been speculated that the use of the color purple was adopted because of the use of purple heart wood from Brazil to make caissons for the artillery.’
    • ‘Graves were everywhere; dead soldiers and horses lay unburied; and destroyed wagons and caissons littered the area.’
    • ‘While most of the army's accomplished horsemen served in the Cavalry, the Field Artillery used horses to draw its caissons, and officers needed to learn to ride adroitly.’
    • ‘It was impossible to resist the line of World War I toys - including doughboys with fixed bayonets and artillery attached to caissons that were pulled by teams of horses.’


Late 17th century: from French, literally ‘large chest’, from Italian cassone, the spelling having been altered in French by association with caisse ‘case’.