Definition of "omicron" in English

noun

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.

   • ... 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.

noun

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