plural noroviruses
: any of a genus (Norovirus) of small, round, single-stranded RNA viruses that includes a single species (N. norwalkense) with various strains causing gastroenteritis in people and animals (such as cows, pigs, and dogs)
People spread the virus by eating food or drinking liquids that are contaminated with norovirus, touching surfaces or objects contaminated with norovirus and then touching their mouth or having direct contact with another person who is infected.Cherie Black

Note: In people, noroviruses cause gastroenteritis marked chiefly by sudden onset diarrhea, vomiting, nausea, and abdominal cramps.

see norwalk virus

Examples of norovirus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
More than 120 people got sick in a norovirus outbreak aboard a Princess Cruises ship, marking the cruise line’s third this year. Nathan Diller, USA Today, 2 July 2026 Meanwhile, another cruise ship heading to Alaska at the end of June also experienced a norovirus outbreak. Adam England, PEOPLE, 3 July 2026 With catering events at watch parties, shared food and drinks, and crowded stadiums, World Cup events represent near-ideal conditions for a norovirus outbreak. Matthew Binnicker, Forbes.com, 10 June 2026 Washing hands frequently is key to preventing a norovirus infection, especially after using the bathroom or before eating and drinking. ABC News, 2 July 2026 See All Example Sentences for norovirus

Word History

Etymology

New Latin, from English Norwalk virus + New Latin -o- + virus

First Known Use

2002, in the meaning defined above

Time Traveler
The first known use of norovirus was in 2002

Browse Nearby Words

Cite this Entry

“Norovirus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/norovirus. Accessed 9 Jul. 2026.

Medical Definition

1
Norovirus : a genus of caliciviruses that includes a single species (Norovirus norwalkense) with various strains causing gastroenteritis in people and animals (such as cows and dogs)
2
: any virus of the genus Norovirus
Norovirus can be transmitted person-to-person (via the fecal-oral route) and spread through contaminated airborne droplets, food, water, environmental surfaces, and fomites.The Journal of the American Medical Association

Note: In people, noroviruses cause gastroenteritis marked chiefly by sudden onset, diarrhea, vomiting, nausea, and abdominal cramps.

see norwalk virus
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