omicronPronunciation: /ə(ʊ)ˈmʌɪkrɒn/Definition of omicron noun the fifteenth letter of the Greek alphabet (Ο, ο), transliterated as ‘o’. (Omicron) [followed by Latin genitive] Astronomy the fifteenth star in a constellation:Omicron PisciumOrigin:from Greek o mikron 'small o'omicron in other Oxford dictionaries Definition of omicron in the US English dictionary
