epinephrinePronunciation: /ˌɛpɪˈnɛfrɪn, -riːn/Definition of epinephrine noun Biochemistry another term for adrenaline.Origin: late 19th century: from epi- 'above' + Greek nephros 'kidney' + -ine4epinephrine in other Oxford dictionaries Definition of epinephrine in the US English dictionary