The Collaborative International Dictionary of English v.0.48:

Suction \Suc"tion\, n. [L. sugere, suctum, to suck; cf. OF.
   suction. See Suck, v. t.]
   The act or process of sucking; the act of drawing, as fluids,
   by exhausting the air.
   [1913 Webster]

   Suction chamber, the chamber of a pump into which the
      suction pipe delivers.

   Suction pipe, Suction valve, the induction pipe, and
      induction valve, of a pump, respectively.

   Suction pump, the common pump, in which the water is raised
      into the barrel by atmospheric pressure. See Illust. of
      Pump.
      [1913 Webster]

WordNet (r) 3.0 (2006):

suction
    n 1: a force over an area produced by a pressure difference
    2: the act of sucking [syn: sucking, suck, suction]
    v 1: remove or draw away by the force of suction; "the doctors
         had to suction the water from the patient's lungs"
    2: empty or clean (a body cavity) by the force of suction;
       "suction the uterus in an abortion"

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "suction":
   aspiration, bleeding, bloodletting, broaching, cupping, drafting,
   drag, drainage, draining, drawing, emptying, favor, inhalation,
   inhalement, inside track, inspiration, interest, milking,
   phlebotomy, pipetting, pull, pumping, siphoning, sniff, sniffle,
   snuff, snuffle, special favor, suck, sucking, tapping,
   venesection