omicron

• Omicron, omikron, Omikron
• o, O
• Ο, ο

From Latin omicron, from Koine Greek ὂ μῑκρόν (ò mīkrón, “little o”), named in contrast with omega (“big o”). The uncommon form omicra is similarly borrowed from Latin and Greek. The use for designating stars in a constellation—typically in order of apparent brightness—began with Johann Bayer's 1603 Uranometria.

• (UK) IPA^(key): /ˈɒmɪkɹɒn/, /ˈɒmɪkɹən/, /ˈəʊmɪkɹɒn/, /əʊˈmaɪkɹɒn/, /əʊˈmaɪkɹən/, /əˈmaɪkɹɒn/, /əˈmaɪkɹən/
• (US) IPA^(key): /ˈoʊməˌkɹɑn/, /ˈoʊmɪˌkɹɑn/, /ˈɑməˌkɹɑn/, /ˈɑmɪˌkɹɑn/

• Audio (US)

  (file)

• Rhymes: -aɪkɹɒn
• Homophone: Omicron

omicron (plural omicrons or omicra)

1. (sometimes capitalized) The 15th letter of the Classical and Modern Greek alphabets (16th in Ancient and Old Greek), used in ordering lists as in naming (astronomy) the 15th star of a constellation or (epidemiology) the 15th discovered major variant of a disease.
   • 1656 [1612], Henry, Earl of Monmouth, transl., I Raggvagli di Parnasso: or Advertisements from Parnassus, London: Humphrey Moseley, translation of De Ragguagli di Parnaso by Traiano Boccalini, page 180:

     Your Majestie knows that unfortunate I [...] was the first who when I published my Poem of Italia Liberata endeavoured to bring the Omicron, Eupselon, Omega, and other Greek Letters, which I thought very requisite for that language, into my own Tongue;

   • 1750 [1748 January 10], James Russel, “Letter LI”, in Letters from a Young Painter Abroad to his Friends in England‎, volume II, London: W. Russel, page 120:

     The E serves both for the Epsilon and Eta; the O, both for the Omicron and Omega, and likewise for the dipthong OΥ.

   • 1992 July, Astronomy Now, No. 36, p. 1:

     ... They include Mira itself (omicron Ceti) which can be seen shortly before dawn.

   • 2021 November 27, Vimal Patel, "How Omicron, the New Covid-19 Variant, Got Its Name", New York Times:

     There are now seven “variants of interest” or “variants of concern” and they each have a Greek letter, according to a W.H.O. tracking page. Some other variants with Greek letters do not reach those classification levels, and the W.H.O. also skipped two letters just before Omicron — “Nu” and “Xi” — leading to speculation about whether “Xi” was avoided in deference to the Chinese president, Xi Jinping.

omicron (uncountable)

1. (virology, pathology) Ellipsis of Omicron variant.

• “omicon, n.”, in OED Online ⁠, Oxford, Oxfordshire: Oxford University Press, 2021.
• “omicron”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• Hauser, Christine. "How Do You Say 'Omicron'?" New York Times, 30 November 2021.
• West, James. "I Asked Seven Classics Experts How to Say 'Omicron'..." Mother Jones, 30 November 2021.

• moronic, oncomir

• IPA^(key): /ɔ.mi.kʁɔ̃/, /ɔ.mi.kʁɔn/

• Audio

  (file)

omicron m (plural omicron or omicrons)

1. omicron (Greek letter)

The plural form omicrons is a product of the 1990 spelling reforms.

• “omicron”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

omicron m (invariable)

1. omicron (Greek letter)

• cromino

Borrowed from French omicron.

omicron m (plural omicron)

1. omicron (Greek letter)