# omicron
## English
### Alternative forms

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

### Etymology

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.

### Pronunciation

* (UK) IPA: /ˈɒmɪkɹɒn/, /ˈɒmɪkɹən/, /ˈəʊmɪkɹɒn/, /əʊˈmaɪkɹɒn/, /əʊˈmaɪkɹən/, /əˈmaɪkɹɒn/, /əˈmaɪkɹən/
* (US) IPA: /ˈoʊməˌkɹɑn/, /ˈoʊmɪˌkɹɑn/, /ˈɑməˌkɹɑn/, /ˈɑmɪˌkɹɑn/
* Audio (US):(file)
* Rhymes: -aɪkɹɒn
* Homophone: Omicron

### Noun

omicron (plural omicrons or omicra)
* (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.

### Noun

omicron (uncountable)
* (virology, pathology) Ellipsis of Omicron variant.

#### Derived terms

* omicron strain
* omicron variant
* omicron virus

#### See also

* (Greek-script letter names) alpha, beta, gamma, delta, epsilon, zeta, eta, theta, iota, kappa, lambda, mu, nu, xi, omicron, pi, rho, sigma, tau, upsilon, phi, chi, psi, omega

### References

* “omicon, n.”, in OED Online ⁠, Oxford: 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.

### Anagrams

* moronic, oncomir

## French
### Pronunciation

* IPA: /ɔ.mi.kʁɔ̃/, /ɔ.mi.kʁɔn/
* Audio:(file)

### Noun

omicron m (plural omicron or omicrons)
* omicron (Greek letter)

#### Usage notes

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

### Further reading

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

## Italian
### Noun

omicron m (invariable)
* omicron (Greek letter)

### Anagrams

* cromino

## Romanian
### Etymology

Borrowed from French omicron.

### Noun

omicron m (plural omicron)
* omicron (Greek letter)