n.
Pronunciation: ' k ā - ˌ sän, -s ə n, Brit also k ə - ' sün
Function: noun
Etymology: French, from Middle French, from Old Occitan, from caissa chest, from Latin capsa ― more at CASE
Date: circa 1702
1 a : a chest to hold ammunition b : a usually 2-wheeled vehicle for artillery ammunition attachable to a horse-drawn limber also : a limber with its attached caisson
2 a : a watertight chamber used in construction work under water or as a foundation b : a hollow floating box or a boat used as a floodgate for a dock or basin
3 : COFFER 3
caisson