sump 
(sŭmp)
(sŭmp)n.
1.
a. A low-lying place, such as a pit, that receives drainage.
b. A cesspool.
2. A hole at the lowest point of a mine shaft into which water is drained in order to be pumped out.
3. The crankcase or oil reservoir of an internal-combustion engine.
[Middle English sompe, marsh, from Middle Low German sump or from Middle Dutch somp. Sense 2, from German Sumpf, swamp, sump, from Middle High German, swamp.]