Why is the conversion of ethanol to ethanoic acid an oxidation reaction?

(N/A) The chemical reaction is represented as: $\text{CH}_3\text{CH}_2\text{OH} \xrightarrow{[O]} \text{CH}_3\text{COOH}$.
An oxidation reaction is defined as the addition of oxygen or the removal of hydrogen from a substance.
In the conversion of ethanol $(\text{CH}_3\text{CH}_2\text{OH})$ to ethanoic acid $(\text{CH}_3\text{COOH})$, an oxygen atom is added to the molecule.
Since oxygen is added to ethanol to form ethanoic acid, this process is classified as an oxidation reaction.