- the 15th letter in the Greek alphabet (Ο, ο), a short vowel, transliterated as o
WordReference Random House Unabridged Dictionary of American English © 2026
om•i•cron
(om′i kron′, ō′mi-),USA pronunciation n.
- Linguisticsthe 15th letter of the Greek alphabet (O, o).
- Linguisticsthe vowel sound represented by this letter.
- Greek ō mikrón, literally, small o. Compare omega
Collins Concise English Dictionary © HarperCollins Publishers::
omicron /əʊˈmaɪkrɒn; ˈɒmɪkrɒn/ n
o•me•ga /oʊˈmeɪgə, oʊˈmɛgə/USA pronunciation
n. [countable], pl. -gas.
WordReference Random House Unabridged Dictionary of American English © 2026- Linguisticsthe 24th and last letter of the Greek alphabet (&Ohgr;, &ohgr;).
- the last of a series;
the end.
o•me•ga
(ō mē′gə, ō mā′-, ō meg′ə),USA pronunciation n.
- the 24th and last letter of the Greek alphabet (Ω, ω).
- the vowel sound represented by this letter.
- the last of any series;
the end.
- Greek ō méga literally, great o. Compare omicron
'omicron' also found in these entries (note: many are not synonyms or translations):