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

The Texas Democrat returned to the campaign trail last weekend after more than a week away with the flu, as conspiracy theories from right-wing activists spread like wildfire across social media. — Lauren Green, The Washington Examiner, 15 Oct. 2026

Pharmacists can give flu and COVID-19 vaccines without a prescription to anyone 3 years and older. — Adejare Atanda, Baltimore Sun, 13 Oct. 2026

Continue reading … GUT FEELING — Want to dodge the flu this year? — FOXNews.com, 13 Oct. 2026

The unusually early start to flu season has prompted local health officials to urge people to get their flu shots as soon as possible. — Assistant Editor, Los Angeles Times, 10 Oct. 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