meaning of caisson
1. A chest to hold ammunition.
2. A four-wheeled carriage for conveying ammunition, consisting of two parts, a body and a limber. In light field batteries there is one caisson to each piece, having two ammunition boxes on the body, and one on the limber.
3. A chest filled with explosive materials, to be laid in the way of an enemy and exploded on his approach.
4. A water-tight box, of timber or iron within which work is carried on in building foundations or structures below the water level.
5. A hollow floating box, usually of iron, which serves to close the entrances of docks and basins.
6. A structure, usually with an air chamber, placed beneath a vessel to lift or float it.
7. A sunk panel of ceilings or soffits.
8. large watertight chamber used for construction under water