• synonyms


See more synonyms for flu on Thesaurus.com
  1. influenza.
  2. a specific variety of influenza, usually named for its point of dissemination or its animal vector: Hong Kong flu; swine flu.
Show More

Origin of flu

First recorded in 1830–40; shortened form
Can be confusedflew flu flue
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for flu

Contemporary Examples

Historical Examples

  • Then he was taken down with the 'flu' and had to give up study.

    Galusha the Magnificent

    Joseph C. Lincoln

  • I wish some of those fellows with the flu could have you to look after them.


    Alice Hegan Rice

  • If he were on Earth, he would be certain it was the flu; in the Centaurus system, kranken.

    Bolden's Pets

    F. L. Wallace

  • If he hadn't gone with the flu, that ranch'd been paid for in another year.

    Polly and Eleanor

    Lillian Elizabeth Roy

  • "Was sure I was coming down with the flu," Clavering mumbled.

    Black Oxen

    Gertrude Franklin Horn Atherton

British Dictionary definitions for flu


noun informal
  1. the flu short for influenza
  2. any of various viral infections, esp a respiratory or intestinal infection
Show More
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for flu


1839, flue, shortening of influenza. Spelling flu attested from 1893. For choice of middle syllable, not a common method of shortening in English, Weekley compares tec for detective, scrip for subscription.

Show More
Online Etymology Dictionary, © 2010 Douglas Harper

flu in Medicine


  1. Influenza.
Show More
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

flu in Science


  1. See influenza.
Show More
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.