Definitions
1.nounA hollow or pit into which liquid drains, such as a cesspool, cesspit or sink.
2.nounThe lowest part of a mineshaft into which water drains.
3.nounA completely flooded cave passage, sometimes passable by diving.
4.nounThe crankcase or oil reservoir of an internal combustion engine.
5.nounThe pit at the lowest point in a circulating or drainage system (FM 55-501).
6.nounAn intentional depression around a drain or scupper that promotes drainage.
7.verbOf a cave passage, to end in a sump, or to fill completely with water on occasion."This low passage sumps quickly after moderate rainfall."