What does aeration mean?
The definition of aeration
A`ër*a”tion, n.
Etym: [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.