ox·i·da·tion 
(ŏk′sĭ-dāshən)
(ŏk′sĭ-dāshən)n.
1. The combination of a substance with oxygen.
2. A reaction in which the atoms of an element lose electrons and the valence of the element is correspondingly increased.
[French, from oxider, to oxidize, from oxide, oxide; see OXIDE.]
oxi·da′tive adj.
oxi·da′tive·ly adv.