Entry 1 sense Webster, 1913 Oxidation /äkˌ-səd-āsh'-ən/ · Ox·i·da·tion · IPA /ˌɑksɪˈdeɪʃ(ə)n/ 01 n. The act or process of oxidizing, or the state or result of being oxidized. 1. The act or process of oxidizing, or the state or result of being oxidized.(Chem.)