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

Symptoms resemble the flu and can take up to two weeks to appear after exposure. —Chris Sims, Louisville Courier Journal, 5 Aug. 2025

This only impacts a relatively small percentage (4%) of flu vaccines administered to Americans. —Joshua P. Cohen, Forbes.com, 1 Aug. 2025

Only 16% of kids diagnosed with ANE had received a flu vaccination within the past year, compared to 49.2% of children overall. —Andrew Zeng, Mercury News, 31 July 2025

The Centers for Disease Control and Prevention (CDC) has ended its emergency response to the H5N1 avian flu. —Alejandra O’Connell-Domenech, The Hill, 8 July 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