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 typically start between seven to 14 days after coming into contact with the virus and may present similarly to the flu, with signs like a cough, runny nose, red/watery eyes and a high fever that may spike to more than 104 degrees. — Finch Walker, USA Today, 27 Aug. 2026

Things could be better, which goes without saying in the aftermath of a flu pandemic that has wiped out most of the planet’s human population, but the four principals here could also be dead, so there’s that. — Guy Lodge, Variety, 26 Aug. 2026

It’s based on Peter Heller’s 2012 novel and set in Colorado 10 years in the future after an aggressive flu has decimated much of the population. — Emily Zemler, Los Angeles Times, 26 Aug. 2026

Elordi plays Hig, a pilot who survived the flu but lost his wife. — Anthony D'alessandro, Deadline, 26 Aug. 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