omicron

noun

1. (capitalized, sometimes)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.

   “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;”

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

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

   “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.”

2. (abbreviation, alt-of, ellipsis, uncountable)Ellipsis of Omicron variant.
3. (abbreviation, alt-of, ellipsis, uncountable)Ellipsis of Omicron variant.
4. (alt-of, alternative, countable)Alternative form of omicron (Greek letter) (especially in the majuscule form)

name

1. (abbreviation, alt-of, ellipsis)Ellipsis of Omicron Hill: a mountain in North Slope borough, Alaska, United States.