caisson

Meanings

1. A (permanent) enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.
2. A structure with similar function that is temporary.
3. A coffer (sunken panel).
4. The gate across the entrance to a drydock.
5. A floating tank that can be submerged, attached to an underwater object and then pumped out to lift the object by buoyancy.
6. A two-wheeled, horse-drawn military vehicle used to carry ammunition (and a coffin at funerals).
7. A large box to hold ammunition.
8. A chest filled with explosive materials, used like a mine.

Etymology

Borrowed from French caisson. Doublet of cassone and cajón.