What is the meaning of Caisson?

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

The gate across the entrance to a dry dock.

A floating tank that can be submerged, attached to an underwater object and then pumped out to lift the object by buoyancy; a camel.

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

A large box to hold ammunition.

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

A coffer.

box

coffer

caisson (military vehicle)

caisson (structure to exclude water)

caisson: an enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc

transport cart

Source: wiktionary.org