Cofferdam (noun)

1. A temporary watertight enclosure built around an area where work is to be done underwater.
2. A barrier built around a construction site that is filled with water to allow work to be done underwater.

Origin:

Derived from the old french word "cofre" meaning chest and "dam" meaning barrier.

Examples:

1. A cofferdam was built to repair the damaged ship's hull.
2. The cofferdam allowed the workers to repair the bridge foundation without being affected by the water.
3. A cofferdam was installed to construct the new underwater tunnel.
4. The cofferdam was filled with water to create a dry working area for the construction crew.
5. The cofferdam was removed after the construction work was completed.