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

Since Operation Warp Speed’s success, federal policymakers have continued to help scientists explore mRNA’s potential to combat other diseases, from flu to hepatitis. —Michael C. Burgess, STAT, 30 Apr. 2026

Means, who has a medical degree but did not complete her residency and does not hold an active medical license, appeared hesitant to say that some vaccines, such as the flu vaccine, prevent serious disease. —Mary Kekatos, ABC News, 30 Apr. 2026

But the ground-ball flu seemed to subside Tuesday night. —Abbey Mastracco, New York Daily News, 29 Apr. 2026

In Florida, though, those disparities result in differences in who went without a dental visit, a flu shot, a colon cancer screening and who ended up in an avoidable emergency department visit. —Cindy Krischer Goodman, Sun Sentinel, 29 Apr. 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