Caisson (noun)

1. A watertight chamber used in construction to keep an area dry, especially for the construction of bridges, piers, and other underwater structures.
2. A military structure used as a mobile floating storeroom or ammunition dump.

Origin:

The word 'caisson' comes from the french word caisse, meaning 'box' or 'chest'.

Examples:

1. The caissons were used to build the foundation of the bridge, allowing the construction to take place underwater.
2. The caissons were an essential part of the construction process, keeping the work area dry and protected from the water.
3. The military used the caissons to store ammunition and supplies, and to transport them to the front line.
4. The caissons were designed to be sturdy and waterproof, to ensure the safety of the stored materials.
5. The caissons were an important part of the military's logistical operations, helping to ensure that the soldiers had the supplies and ammunition they needed.