ETYM French, from caisse, case, chest. Related to Case.
1. A chest to hold ammunition; SYN. ammunition chest.
2. A two-wheeled vehicle carrying artillery ammunition.
3. Large watertight chamber used for construction under water; SYN. pneumatic caisson, cofferdam.
Vehicle or chest for holding ammunition.
Underwater water-tight chamber for bridge-building, etc.; hydraulic lift for raising ship; Military, ammunition wagon. caisson disease, condition, marked by pain, paralysis or death, due to over-rapid lowering of air pressure after working in compressed air; “the bends”.
Hollow cylindrical or boxlike structure, usually of reinforced concrete, sunk into a riverbed to form the foundations of a bridge.
An open caisson is open at the top and at the bottom, where there is a wedge-shaped cutting edge. Material is excavated from inside, allowing the caisson to sink. A pneumatic caisson has a pressurized chamber at the bottom, in which workers carry out the excavation. The air pressure prevents the surrounding water entering; the workers enter and leave the chamber through an air lock, allowing for a suitable decompression period to prevent decompression sickness (the so-called bends).