Definition

1. Noun:
   • Large watertight chamber used for construction under water: A caisson is a sealed, watertight structure used to create a dry working environment for building foundations, bridge piers, or other structures in bodies of water.
   • A chest to hold ammunition: A caisson is a sturdy box or chest designed to store and transport artillery shells and other ammunition.
   • A two-wheeled military vehicle carrying artillery ammunition: A caisson is a horse-drawn or motorized cart with two wheels, used to carry ammunition and often accompanying artillery pieces.
   • An ornamental sunken panel in a ceiling or dome: In architecture, a caisson is a decorative, recessed panel, often found in ceilings, vaults, or domes, sometimes called a coffer.

Usage Examples

• Noun (Watertight Chamber):
  • Workers descended into the caisson to excavate the riverbed for the bridge's foundation.
  • The caisson was slowly sunk to the seabed to provide a dry workspace.
• Noun (Ammunition Chest):
  • The soldiers carefully loaded the shells into the iron caisson.
  • The ammunition caisson was kept locked and secure.
• Noun (Military Vehicle):
  • The artillery battery advanced, each gun followed by its caisson.
  • The horses pulled the heavy caisson across the field.
• Noun (Architectural Panel):
  • The dome's interior was adorned with intricate gilded caissons.
  • The ceiling's design featured a grid of beautifully painted caissons.

Advanced Usage

• "Caisson disease": Also known as decompression sickness or "the bends," this is a medical condition caused by dissolved gases forming bubbles in the bloodstream when a person surfaces too quickly from a high-pressure environment, such as a watertight caisson. While "caisson" is part of the compound term, the condition is named for the work environment.
  • Early divers and caisson workers were at high risk of developing caisson disease.

Variants and Related Words

• Coffered ceiling (n): A ceiling decorated with a pattern of recessed panels (caissons).
  • The palace's grand hall featured an ornate coffered ceiling.
• Pontoon (n): A flat-bottomed boat or floating structure, sometimes used in a similar context for flotation. (Note: This is a related but distinct concept from a watertight working chamber).

Synonyms

• Watertight chamber: Cofferdam, diving bell (context-specific).
• Ammunition chest: Ammo box, cartridge case.
• Military vehicle: Ammunition wagon, limber (a related vehicle for towing artillery).
• Sunken panel: Coffer, lacunar.

Related Phrases

• "To sink a caisson": The process of lowering a watertight chamber into position for underwater construction.
  • The engineering team prepared to sink the first caisson for the new pier.

Noun

1. large watertight chamber used for construction under water
2. a chest to hold ammunition
3. a two-wheeled military vehicle carrying artillery ammunition
4. an ornamental sunken panel in a ceiling or dome