[sump] n [ME sompe swamp--more at swamp] (1653) 1: a pit or reservoir serving as a drain or receptacle for liquids: as a: cesspool b: a pit at the lowest point in a circulating or drainage system (as the oil-circulating system of an internal combustion engine) c chiefly Brit: oil pan
2. Brit: crankcase 3 [G Sumpf, lit., marsh, fr. MHG--more at swamp] a: the lowest part of a mine shaft into which water drains b: an excavation ahead of regular work in driving a mine tunnel or sinking a mine shaft
4: something resembling a sump: sink
2.