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1920, Modern Latin, from Greek an-, privative prefix, "not, without" (see an- (1)) + first two letters of oxygen + -ic. Anoxia "oxygen deficiency" is attested from 1931.
anoxia an·ox·i·a (ān-ŏk'sē-ə, ə-nŏk'-)n. The absence or reduced supply of oxygen in inspired gases, arterial blood, or tissues.