n. [ Cf. F. aération. ] 1. Exposure to the free action of the air; airing; as, aëration of soil, of spawn, etc. [ 1913 Webster ]
2. (Physiol.) A change produced in the blood by exposure to the air in respiration; oxygenation of the blood in respiration; arterialization. [ 1913 Webster ]
3. The act or preparation of charging a liquid with carbon dioxide gas to make it effervescent. [ 1913 Webster ]
4. the act of charging a liquid with air or oxygen for the purpose of purification. [ WordNet 1.5 +PJC ]