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omicron

American  
[om-i-kron, oh-mi-] / ˈɒm ɪˌkrɒn, ˈoʊ mɪ- /

noun

  1. the 15th letter of the Greek alphabet (O,o ).

  2. the vowel sound represented by this letter.


omicron British  
/ ˈɒmɪkrɒn, əʊˈmaɪkrɒn /

noun

  1. the 15th letter in the Greek alphabet (Ο, ο), a short vowel, transliterated as o

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of omicron

< Greek ō mikrón, literally, small o. Cf. omega

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Washington’s manic quarantining of cruise-ship passengers, its restricting of foreign entry, probably did next to nothing to slow spread until a vaccine and the less-virulent omicron variants arrived, which took a year.

From The Wall Street Journal ● Aug. 7, 2026

A show-threatening omicron shutdown, illness and the loss of Adam, who passed away at the end of April 2023.

From Los Angeles Times ● May 29, 2024

This decline was evident among those infected in the early phase of the pandemic and those infected when the delta and omicron variants were dominant.

From Salon ● Mar. 12, 2024

That single-target vaccine replaced combination shots that had been targeting both the original coronavirus strain and a much earlier omicron version.

From Seattle Times ● Feb. 28, 2024

Zero never worked its way into ancient Western numbers, so it is unlikely that the omicron is the mother of our 0.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

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