au·tox·i·da·tion \ȯˌtäksə̇ˈdāshən, ȯd.ˌäk-\noun alsoau·to-ox·idation\| ̷ ̷ ̷ ̷ at auto- I+ ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷\ Etymology: International Scientific Vocabulary aut- + oxidation : oxidation by direct combination with oxygen (as in air) at ordinary temperatures < the rancidity of fats and oils is caused by autoxidation >