flu

noun

ˈflü How to pronounce flu (audio)
1
: influenza
2
: any of several virus diseases marked especially by respiratory or intestinal symptoms
flu-like
ˈflü-ˌlīk How to pronounce flu (audio)
adjective

Examples of flu in a Sentence

He came down with a bad bout of the flu.
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.
Many people infected may never show symptoms, and others will only experience mild, flu-like symptoms. — Irene Wright, USA Today, 3 Sep. 2026 In The Dog Stars, Elordi, 29, plays a man living in Colorado in the near future, some time after a flu pandemic has killed off much of humanity. — Tommy McArdle, PEOPLE, 2 Sep. 2026 Meanwhile, flu and COVID infections are on the rise, students are returning to school, and the fall and winter respiratory season is approaching. — Rob Stein, NPR, 2 Sep. 2026 According to the federal Centers for Disease Control and Prevention, listeria can cause flu-like symptoms, including fever, body aches and fatigue. — Sacbee.com, 2 Sep. 2026 See All Example Sentences for flu

Word History

Etymology

by shortening

First Known Use

1839, in the meaning defined at sense 1

Time Traveler
The first known use of flu was in 1839

Phrases Containing flu

Rhymes for flu

See All Rhymes for flu

Browse Nearby Words

fltg
flu
fluate
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Cite this Entry

“Flu.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/flu. Accessed 4 Sep. 2026.

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Kids Definition

flu

noun
ˈflü How to pronounce flu (audio)
1
: influenza sense 1
2
: any of several virus diseases that are something like a cold
flu-like
ˈflü-ˌlīk
adjective

Medical Definition

flu

noun
ˈflü How to pronounce flu (audio)
1
: influenza
2
: any of several chiefly viral illnesses marked especially by respiratory or gastrointestinal symptoms see intestinal flu
flu-like
-ˌlīk How to pronounce flu (audio)
adjective
also flulike
flu-like symptoms

More from Merriam-Webster on flu

Britannica.com: Encyclopedia article about flu

Last Updated: - Updated example sentences
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