1) Action 2) Activity 3) Natural action 4) Natural process 
The addition of oxygen in the wort. This is done to help provide the yeast with oxygen for a healthy fermentation.
[environmental] Environmental oxygenation can be important to the sustainability of a particular ecosystem. Insufficient oxygen (environmental hypoxia) may occur in bodies of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such as fish. Deoxygenation increases the relative population of anaerobic organi...
• (n.) The act or process of combining or of treating with oxygen; oxidation.
the process of supplying, treating, or mixing with oxygen.
The process of supplying, treating or mixing with oxygen. ... (18 Nov 1997) ... 
(ok″sĭ-jә-na´shәn) the act or process of adding oxygen to something. saturation with oxygen. extracorporeal membrane oxygenation(ECMO) a technique of providing respiratory support; the blood is circulated through an artificial lung co...
Ox`y·gen·a'tion noun [ Confer French oxygénation .] (Chemistry) The act or process of combining or of treating with oxygen; oxidation. 
Type: Term Pronunciation: ok′si-jĕ-nā′shŭn Definitions: 1. Addition of oxygen to any chemical or physical system. 2. Specifically used to describe interventions that provide greater oxygen supply to lungs and thus the circulation.
Oxygenation: The addition of oxygen to any system, including the human body. Oxygenation may also refer to the process of treating a patient with oxygen, or of combining a medication or other substance with oxygen. Hyperbaric oxygenation is an increased amount of oxygen in organs and tissues resulting from the administration of oxygen in a compress...
[n] - the process of providing or combining or treating with oxygen
oxygenation A saturation of or a combination with oxygen, as with the aeration of the blood in the lungs.
noun the process of providing or combining or treating with oxygen; `the oxygenation of the blood`
The addition of oxygen in the wort. This is done to help provide the yeast with oxygen for a healthy fermentation.