\ ˈflü How to pronounce flu (audio) \

Definition of flu

1 : influenza
2 : any of several virus diseases marked especially by respiratory or intestinal symptoms

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Other Words from flu

flu-like \ ˈflü-​ˌlīk How to pronounce flu-like (audio) \ adjective

Examples of flu in a Sentence

He came down with a bad bout of the flu.

Recent Examples on the Web

Instead, use common sense to take care of yourself year-round: Wash your hands, get enough sleep, and get a flu shot. Good Housekeeping, "Exactly What to Eat to Boost Your Immune System, According to a Registered Dietitian," 30 Jan. 2019 According to a 2013 study, having the humidity levels above 40 percent significantly decreases the power of the flu virus. Elizabeth Gulino, House Beautiful, "Want to Avoid the Flu This Season? Buy a House Plant," 26 Feb. 2019 And the students embark on their own investigation in parallel with the CDC to track down the source of a dangerous flu virus that sickened one of their friends at a county fair. Rachel Becker, The Verge, "Junior Disease Detectives is for teens — but I geeked out over it, too," 11 Aug. 2018 The latter class is not recommended for use because flu viruses quickly develop resistance to them. Helen Branswell, STAT, "A flu drug — shown to reduce the duration of symptoms — could upend treatment in U.S.," 27 June 2018 And flu viruses are relatively huge, plus most of their surface is highly mutable. Bradley J. Fikes, sandiegouniontribune.com, "By luck, Scripps Research scientists find clue to a powerful new class of flu drugs," 2 Apr. 2018 The arrival of a threat, such as a flu virus reproducing in the lungs, activates the cells, galvanizing them to combat the invader. Mitch Leslie, Science | AAAS, "To treat some diseases, researchers are putting immune cells on a diet," 29 Mar. 2018 This year, many people came down with the flu virus and experienced fever, coughing, sneezing, and aches and pains. Kitty Leshay, Courant Community, "The Mill: More Than A Museum," 27 Mar. 2018 The Centers For Disease Control estimates more than 14,000 Americans were hospitalized with the flu virus since October. Jason Duaine Hahn, PEOPLE.com, "27-Year-Old Texas Fitness Trainer Who Exercised 'All the Time' Dies of the Flu," 9 Feb. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'flu.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of flu

1839, in the meaning defined at sense 1

History and Etymology for flu

by shortening

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Statistics for flu

Last Updated

14 Apr 2019

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Time Traveler for flu

The first known use of flu was in 1839

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More Definitions for flu



English Language Learners Definition of flu

: a common disease that is caused by a virus and that causes fever, weakness, body aches, and breathing problems


\ ˈflü How to pronounce flu (audio) \

Kids Definition of flu

1 : influenza
2 : any of several virus diseases something like a cold


\ ˈflü How to pronounce flu (audio) \

Medical Definition of flu

1 : influenza
2 : any of several chiefly viral illnesses marked especially by respiratory or gastrointestinal symptoms — see intestinal flu

Other Words from flu

flu-like \ -​ˌlīk How to pronounce flu-like (audio) \ also flulike adjective
flu-like symptoms

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More from Merriam-Webster on flu

Rhyming Dictionary: Words that rhyme with flu

Spanish Central: Translation of flu

Nglish: Translation of flu for Spanish Speakers

Britannica English: Translation of flu for Arabic Speakers

Britannica.com: Encyclopedia article about flu

Comments on flu

What made you want to look up flu? Please tell us where you read or heard it (including the quote, if possible).


not to be persuaded, moved, or stopped

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