flu

noun

ˈflü 

1

: influenza

2

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

flu-like

ˈflü-ˌlīk 

adjective

Examples of flu in a Sentence

He came down with a bad bout of the flu.

Recent Examples on the Web

In fact, of more than 83,000 flu samples tested within the past year, just three cases were detected. —Erika Edwards, NBC News, 16 Jan. 2025

Bird flu began rapidly spreading in the United States in recent years, McClatchy News reported. —Mike Stunson, Kansas City Star, 16 Jan. 2025

As the bird flu outbreak grows, consumers may worry about that morning omelet and the flu's spread to humans. —Kelly Tyko, Axios, 16 Jan. 2025

Kevin Dietsch/Getty Images Bird flu's unprecedented spread among livestock and other mammals in the U.S. has raised fears that another pandemic could be in store. —Will Stone, NPR, 16 Jan. 2025

Word History

Etymology

by shortening

First Known Use

1839, in the meaning defined at sense 1

Phrases Containing flu

• anti-flu
• Asian flu
• bird flu
• blue flu
• flu season
• swine flu
• yuppie flu

Kids Definition

flu

noun

ˈflü 

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 

1

: influenza

2

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

flu-like

-ˌlīk 

adjective

also flulike

flu-like symptoms