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

Beyond flu shots, people should avoid people who are coughing and sneezing, which is how flu spreads. —Eduardo Cuevas, USA Today, 31 Jan. 2026

Among lab test results reported to the CDC during the week ending January 24, 87% involved A strains of the flu, while about 13% were from B strains. —Brenda Goodman, CNN Money, 30 Jan. 2026

One parent said her son missed seven days of school in January because of unclean conditions during flu and virus season. —Bri Hatch, Chalkbeat, 30 Jan. 2026

Our state is 17th in flu activity, and a new flu strain is making things even more challenging. —Aj Willingham, AJC.com, 30 Jan. 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
• 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