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

State health officials will add flu data to its respiratory virus dashboard during the fall flu season, and in the mean time the agency recommends everyone over 6 months of age should stay up to date on COVID-19 vaccinations to protect against severe illness and current variants. —Brooke Baitinger, Sacbee.com, 12 Sep. 2025

Ladapo’s predecessors stressed the importance of hepatitis A vaccines and flu shots. —Lawrence Mower, Miami Herald, 12 Sep. 2025

Staying up to date on yearly immunizations, especially the flu and COVID vaccines, can lower these risks and keep your child breathing easier. —Rhonda Conner-Warren, The Conversation, 11 Sep. 2025

Children infected with the virus may go through the standard disease progression—flu-like symptoms, high fever, the telltale rash—and then appear to fully recover. —Beth Mole, ArsTechnica, 11 Sep. 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