Sump

Part of speech: noun (n.)

1. A round pit of stone, lined with clay, for receiving the metal on its first fusion. Ray.

2. The cistern or reservoir made at the lowest point of a mine, from which is pumped the water which accumulates there.

3. A pond of water for salt works. Knight.

4. A puddle or dirty pool. [Prov. Eng.] Sump fuse, a fuse used in blasting under water. -- Sump men (Mining), the men who sink the sump in a mine.