caisson

Etymology

Borrowed from French caisson. Doublet of cassone and cajón.

noun

1. (engineering">engineering) An enclosure from which water can be expelled, in order to give access to underwater areas for engineering">engineering works etc.
   During the construction of the viaduct, the sinking of the caissons in the river bed caused much difficulty to the engineer and contractors, as a bed of running sand was encountered; in consequence, the expenditure for these foundations proved almost prohibitive. 1946 January and February, “Notes and News: Demolition of Rhydyfelin Viaduct”, in Railway Magazine, page 53
   Caissons were enclosed dry chambers built on river beds to facilitate the construction of bridge piers. 2003, Bill Bryson, A Short History of Nearly Everything, BCA, page 213
2. The gate across the entrance to a dry dock.
3. (nautical) A floating tank that can be submerged, attached to an underwater object and then pumped out to lift the object by buoyancy; a camel.
4. (military) A two-wheeled, horse-drawn military vehicle used to carry ammunition (and a coffin at funerals).
   Over hill, over dale / As we hit the dusty trail, / And those caissons go rolling along. 1908, Edmund Louis Gruber (lyrics and music), “The Caissons Go Rolling Along”
5. (military) A large box to hold ammunition.
6. (military) A chest filled with explosive materials, used like a mine.
7. (architecture) A coffer.