caisson

noun

1. 1

   An enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.

2. 2

   The gate across the entrance to a dry dock.

3. 3

   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. 4

   A two-wheeled, horse-drawn military vehicle used to carry ammunition (and a coffin at funerals).

5. 5

   A large box to hold ammunition.

6. 6

   A chest filled with explosive materials, used like a mine.

7. 7

   A coffer.