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

How bad the flu season gets each year depends on factors such as the dominant flu strain, how well the annual vaccine matches it, how many people get vaccinated, tourism levels, and how much cold weather leads to more indoor gatherings. — Cindy Krischer Goodman, Sun Sentinel, 28 Oct. 2026

And for the first time in years, the agency has not held a flu vaccine awareness campaign ahead of flu season, leaving independent organizations to issue their own guidance. — Adam Kovac, Scientific American, 27 Oct. 2026

Nearly 14% of individuals have received a flu vaccine for the 2026-27 season so far, according to the North Carolina Department of Health and Human Services. — Eva Flowe october 27, Charlotte Observer, 27 Oct. 2026

Historically, Idahoans get flu vaccines at some of the lowest rates in the country. — Mark Dee, Idaho Statesman, 24 Oct. 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