omicron

noun

om·i·cron ˈō-mə-ˌkrän

ˈä-mə-ˌkrän

British also ō-ˈmī-(ˌ)krän

plural omicrons

: the 15th letter of the Greek alphabet see Alphabet Table

or less commonly Omicron : omicron variant

The speed of omicron's rise is quicker than the rise of previous variants of the virus, said Hannah Barbian, a Rush University Medical Center virologist who worked on the testing.—

Sarah Freishtat

How a Virus Got Its Name: Usage Guide

In November 2021, a COVID-19 variant was named Omicron, after the 15th letter of the Greek alphabet. The World Health Organization uses Greek letters to name variants, because these names are easier to communicate than scientific designations like B.1.617.2. According to the WHO, the 13th and 14th Greek letters (nu and xi) were skipped over because "nu" sounds like "new," and "xi" is also a common surname.

How to Pronounce Omicron: Usage Guide

The pronunciation of omicron has several variant forms acceptable in standard English. In American English, the primary stress is usually on the first syllable, pronounced as either a short \o\ as \ˈä-mə-ˌkrän\ or a long \o\ as \ˈō-mə-ˌkrän\. In British English, the primary stress can also be heard on the second syllable: \ō-ˈmī-(ˌ)krän\.

Example Sentences

Recent Examples on the Web The previous booster shots, authorized last fall, were bivalent shots that targeted subvariants of omicron as well as the original strain of the virus. —

Will Sullivan, Smithsonian Magazine, 16 June 2023 Zhong Nanshan, a top Chinese epidemiologist, said Monday that two new vaccines for the XBB omicron subvariants (including XBB. 1.9.1, XBB. 1.5, and XBB. 1.16) had received initial approval, according to state media reports. —

Lily Kuo, Washington Post, 24 May 2023 Not surprisingly, many of the study's early recruits eventually tested positive for the virus, especially after the highly contagious omicron took hold in 2022. —

Erika Edwards, NBC News, 11 Mar. 2023 The bivalent vaccine booster designed to protect against the BA.5 omicron subvariant appears to also be effective in protecting from symptomatic XBB.1.5 infections, according to research the Centers for Disease Control and Prevention published Wednesday. —

oregonlive, 25 Jan. 2023 The latest shots were reformulated last year to target the BA.4 and BA.5 strains of omicron that were dominant in the fall. —

Madison Muller, Fortune, 18 Apr. 2023 The reason the delta wave and the original form of covid seem more likely to produce such symptoms than the more recent omicron and its subvariants is not fully understood. —

Amy Goldstein, Dan Keating, Anchorage Daily News, 18 Mar. 2023 In this case, XBB is a combination of the omicron subvariants BA.2.10.1 and BA.2.75. —

Dallas News, 4 Jan. 2023 Still, the possibility of such outbreaks remains, and the virus continues to evolve, with the latest omicron subvariants XBB.1.5, now predominant nationally, and XBB.1.16 gaining ground. —

Beth Mole, Ars Technica, 3 May 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'omicron.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.