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

For antidepressants, clinicians watch for withdrawal symptoms including sleep problems, flu-like symptoms, headaches and an electrical buzzing sensation in the head. — Andrew McLean, The Conversation, 10 Sep. 2026

For instance, one of Kennedy’s first actions as health secretary last year was to obliterate an ad campaign for flu shots amid a particularly deadly flu season. — Beth Mole, ArsTechnica, 9 Sep. 2026

And the change is coming into effect when the country is heading toward the flu and respiratory virus season. — Helen Branswell, STAT, 9 Sep. 2026

Yet the city has no monument to its flu victims or to the doctors and nurses who cared for them. — Robert W. Snyder, New York Daily News, 6 Sep. 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