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

Using over-the-counter cold and flu medication to get high is far from a new teenage activity; however, calls to poison control for related overdoses continue to spike year-over-year, according to a new America’s Poison Centers alert. —Mary Walrath-Holdridge, USA Today, 12 June 2026

The main risks are familiar viruses like influenza, also known as the flu, said Shruti Gohil, professor of infectious diseases at UC Irvine School of Medicine. —Grant Stringer, Mercury News, 12 June 2026

Leptospirosis is usually asymptomatic but can present flu-like symptoms, officials said. —Tim Fang, CBS News, 11 June 2026

For example, virtual care may be a convenient option for flu-like symptoms, allergies, rashes, or sinus infections, while urgent care may be more appropriate for sprains, ear pain, or minor injuries. —Anthem Blue Cross California, Daily News, 10 June 2026

Word History

Etymology

by shortening

First Known Use

1839, in the meaning defined at sense 1

Phrases Containing flu

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

Rhymes for flu

• blew
• blue
• boo
• brew
• chew
• chou
• clue
• coo
• coup
• crew
• cue
• dew

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