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

This phenomenon seemed to occur in 2009 when older people often fared better at fighting off H1N1, the novel flu strain that jumped to humans from pigs. —Paul Sisson, The Mercury News, 3 Mar. 2025

This was also the first season since the start of the Covid-19 pandemic that flu hospitalizations surpassed those from Covid-19. —Deidre McPhillips, CNN, 28 Feb. 2025

Nasal washes and rinses are meant to temporarily ease symptoms of cold and flu, sinusitis, and allergies. —Tom Gavin, EverydayHealth.com, 28 Feb. 2025

In addition, the body's response to common vaccinations, like those for the flu, tends to be less robust. —Amanda Castro, Newsweek, 28 Feb. 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