Source : Webster's Revised Unabridged Dictionary (1913)

Cesspool \Cess"pool`\ (-p[=oo]l`), n. [See {Sesspol}.]
   A cistern in the course, or the termination, of a drain, to
   collect sedimentary or superfluous matter; a privy vault; any
   receptacle of filth. [Written also {sesspool}.]

Source : WordNet®

cesspool
     n : a covered cistern; waste water and sewage flow into it [syn:
          {cesspit}, {sink}, {sump}]