Source : Webster's Revised Unabridged Dictionary (1913)

Aspirator \As"pi*ra`tor\, n.
   1. (Chem.) An apparatus for passing air or gases through or
      over certain liquids or solids, or for exhausting a closed
      vessel, by means of suction.

   2. (Med.) An instrument for the evacuation of the fluid
      contents of tumors or collections of blood.

Source : WordNet®

aspirator
     n : a pump that draws air or another gas through a liquid