Source : Webster's Revised Unabridged Dictionary (1913)

Aeration \A`["e]r*a"tion\, n. [Cf. F. a['e]ration.]
   1. Exposure to the free action of the air; airing; as,
      a["e]ration of soil, of spawn, etc.

   2. (Physiol.) A change produced in the blood by exposure to
      the air in respiration; oxygenation of the blood in
      respiration; arterialization.

   3. The act or preparation of charging with carbonic acid gas
      or with oxygen.

Source : WordNet®

aeration
     n 1: the process of exposing to air (so as to purify)
     2: the act of charging a liquid with a gas making it
        effervescent