Source : Webster's Revised Unabridged Dictionary (1913)

Sump \Sump\, n. [Cf. G. sumpf a sump in a mine, a swamp, akin to
   LG. sump, D. somp a swamp, Dan. & Sw. sump, and perhaps to E.
   swamp.]
   1. (Metal.) 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.

Source : WordNet®

sump
     n 1: an oil reservoir in an internal combustion engine
     2: a well or other hole in which water has collected
     3: a covered cistern; waste water and sewage flow into it [syn:
         {cesspool}, {cesspit}, {sink}]