# caisson

> English word · Noun · IPA /ˈkeɪ.sən/ · frequency rank #80,285

## Definitions
1. An enclosure from which water can be expelled, in order to give access to underwater areas for engineering works etc.
2. The gate across the entrance to a dry dock.
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. A two-wheeled, horse-drawn military vehicle used to carry ammunition (and a coffin at funerals).
5. A large box to hold ammunition.
6. A chest filled with explosive materials, used like a mine.
7. A coffer.

## Etymology
Borrowed from French caisson. Doublet of cassone and cajón.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/caisson