A`ër*a"tion (&?;), n. [Cf. F. aération.] 1. Exposure to the free action of the air; airing; as, aëration 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.