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

Bird flu is not a big concern for songbirds, but other diseases, such as conjunctivitis, can affect them. —Rebecca Jones, Southern Living, 2 May 2025

North Carolina sits along a popular flyway for migrating birds, which can spread avian flu from farm to farm, says the U.S. Department of Agriculture. —Gavin Off, Charlotte Observer, 30 Apr. 2025

The health benefits of wild garlic Wild garlic appears to have a host of healthy properties and has long been used in Europe and Asia as a homeopathic remedy for everything from toothaches to bloating to the flu. —Christina Pérez, Vogue, 30 Apr. 2025

Inactivated whole-virus flu vaccines are still used in some other countries. —Meg Tirrell, CNN Money, 1 May 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

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