caisson

noun

cais·​son ˈkā-ˌsän 

-sᵊn,

 British also  kə-ˈsün

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 sense 3

Illustration of caisson

• caisson 1b

Examples of caisson in a Sentence

Recent Examples on the Web

In June 2025, the caisson program restarted following an $18 million overhaul by the Army. —Andrew Paul, Popular Science, 9 July 2025

The refurbishment included a complete overhaul, including a paint job, the repairing of caisson cracks, window and door replacements, cleaning and re-pointing of the foundation masonry, restoring all wood floors, and reconstruction of the intermediate landing between the bridge and gangway. —Michael P. McKinney, USA Today, 7 June 2025

In February, Bally’s began driving foundational caissons into the ground, with executives targeting a September 2026 opening for the casino. —Robert Channick, Chicago Tribune, 14 May 2025

The caisson horses in service before the pause have been rehabilitated and retired, and since then, the Army has procured 46 horses. —Eleanor Watson, CBS News, 8 Apr. 2025

Word History

Etymology

French, from Middle French, from Old Occitan, from caissa chest, from Latin capsa — more at case

First Known Use

circa 1702, in the meaning defined at sense 1a

Phrases Containing caisson

• caisson disease

Rhymes for caisson

• basin
• chasten
• hasten
• jason
• capsaicin
• freemason
• stonemason
• subbasin
• washbasin
• indomethacin

Kids Definition

caisson

noun

cais·​son ˈkā-ˌsän 

ˈkā-sᵊn

1

a

: a chest for ammunition

b

: a usually two-wheeled vehicle for artillery ammunition

2

: a watertight chamber used in construction work underwater or as a foundation