n. (Metal.) A round pit of stone, lined with clay, for receiving the metal on its first fusion. The cistern or reservoir made at the lowest point of a mine, from which is pumped the water which accumulates there. A pit or similar storage area in a basement for collecting drained liquid waste. A pond of water for salt works. A puddle or dirty pool. Sump fuse, a fuse used in blasting under water.
- Sump men (Mining), the men who sink the sump in a mine.