1
2
: any of several virus diseases marked especially by respiratory or intestinal symptoms
Examples of flu in a Sentence
He came down with a bad bout of the flu.
Recent Examples on the Web
Key Takeaways The ketogenic diet may cause the keto flu as your body adjusts to using ketones for energy.
—
Brittany Lubeck, Verywell Health, 28 Nov. 2025
Fever protected against severe infection from human-origin flu viruses, the team reported, with just a 2°C increase in body temperature enough to turn a lethal infection into a mild disease.
—Health Reporter, MSNBC Newsweek, 27 Nov. 2025
Mice infected with the heat-resistant strain got sick, but those infected with the normal strain seemed relatively unscathed, suggesting the heat itself helped fight off the flu.
—NPR, 27 Nov. 2025
Just over half have either received the flu vaccine for their children or plan to, while the other half either do not intend to vaccinate their children or are still unsure.
—Sarah Scott, Parents, 25 Nov. 2025
See All Example Sentences for flu
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Brittany Lubeck, Verywell Health, 28 Nov. 2025
Fever protected against severe infection from human-origin flu viruses, the team reported, with just a 2°C increase in body temperature enough to turn a lethal infection into a mild disease.
—Health Reporter, MSNBC Newsweek, 27 Nov. 2025
Mice infected with the heat-resistant strain got sick, but those infected with the normal strain seemed relatively unscathed, suggesting the heat itself helped fight off the flu.
—NPR, 27 Nov. 2025
Just over half have either received the flu vaccine for their children or plan to, while the other half either do not intend to vaccinate their children or are still unsure.
—Sarah Scott, Parents, 25 Nov. 2025
See All Example Sentences for flu
Cite this Entry
“Flu.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/flu. Accessed 30 Nov. 2025.
Copy CitationKids Definition
flu
noun2
: any of several virus diseases that are something like a cold
flu-like
adjective
ˈflü-ˌlīk
Medical Definition
flu
noun1
2
: any of several chiefly viral illnesses marked especially by respiratory or gastrointestinal symptoms see intestinal flu
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