influenza

noun
in·​flu·​en·​za | \ ˌin-(ˌ)flü-ˈen-zə \

Definition of influenza

1a : an acute, highly contagious, respiratory disease caused by any of three orthomyxoviruses:
(1) or influenza A : moderate to severe influenza that in humans is marked especially by sudden onset, fever, sore throat, fatigue, muscle aches, inflammation of the respiratory mucous membranes, and cough, that has numerous variants caused by subtypes (such as H1N1, H2N2, or H3N2) of an orthomyxovirus (species Influenza A virus of the genus Influenzavirus A) infecting humans and various animals (such as birds or pigs), and that may occur in seasonal epidemics or sometimes pandemics following mutation in the causative virus
(2) or influenza B : influenza with less severe symptoms that is caused by an orthomyxovirus (species Influenza B virus of the genus Influenzavirus B) infecting only humans and especially children and that may occur in seasonal epidemics but not pandemics
(3) or influenza C : mild influenza that is often asymptomatic, is caused by an orthomyxovirus (species Influenza C virus of the genus Influenzavirus C) infecting only humans, and does not occur in epidemics or pandemics
b : any of various human respiratory infections of undetermined cause not used technically
2 : any of various virus diseases of domestic animals marked especially by fever, respiratory symptoms, and inflammation of mucous membranes

Note: All types of influenza are commonly called "the flu."

Keep scrolling for more

Other Words from influenza

influenzal \ ˌin-​(ˌ)flü-​ˈen-​zəl \ adjective
influenzal pneumonia influenzal symptoms

Examples of influenza in a Sentence

Recent Examples on the Web

Despite the medical advancements and innovations of the past 100 years, the world remains unprepared for when, not if, the next influenza pandemic emerges. Sy Mukherjee, Fortune, "Commentary: A $12 Million Innovation Prize for a Universal Flu Vaccine," 30 Apr. 2018 Although most of the Indiana deaths have occurred in people over the age of 65, nearly 83 percent of those reporting influenza-like illnesses are age 24 and younger. Nancy Coltun Webster, Post-Tribune, "A mother grieves after her daughter's flu-related death: 'She wanted to get married'," 15 Feb. 2018 One hundred years ago, the deadliest influenza pandemic of all time made a ravaging march across the globe. Dennis Thompson, chicagotribune.com, "Could the deadly 1918 flu pandemic happen again?," 9 Feb. 2018 Leading scientists and public health officials have the capability to keep us much safer from devastating influenza pandemics. Time, "Our Complacency About the Flu is Killing Us," 19 Jan. 2018 Health officials announced Friday that two children were sickened by a rare strain of influenza after coming into contact with pigs at a county fair in Michigan. Michelle Gant, Fox News, "Michigan county fair attendees test positive for rare strain of swine flu," 13 Aug. 2018 This variant of influenza is most commonly associated with contact with pigs, the Indiana State Department of Health and Indiana Board of Animal Health said in a statement Friday. Emma Kate Fittes, Indianapolis Star, "Indiana resident catches rare form of flu following exposure to pigs at a county fair," 1 July 2018 And there is always the issue of influenza itself, changing and mutating a lot some years, and not at all in others. NBC News, "Flu shot fail: Why doesn't the vaccine always work?," 15 Feb. 2018 Less than a year after the United States entered World War I, an unprecedented outbreak of influenza swept the world, killing more people than the war. Kelly Kazek, AL.com, "How the 1918 Spanish flu pandemic changed Alabama," 16 Jan. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'influenza.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of influenza

1743, in the meaning defined at sense 1a

History and Etymology for influenza

Italian, literally, influence, from Medieval Latin influentia; from the belief that epidemics were due to the influence of the stars

Keep scrolling for more

Learn More about influenza

Dictionary Entries near influenza

influencive

influent

influential

influenza

influx

influxion

info

Statistics for influenza

Last Updated

13 Jan 2019

Look-up Popularity

Time Traveler for influenza

The first known use of influenza was in 1743

See more words from the same year

Keep scrolling for more

More Definitions for influenza

influenza

noun

English Language Learners Definition of influenza

medical : a common illness that is caused by a virus and that causes fever, weakness, severe aches and pains, and breathing problems

influenza

noun
in·​flu·​en·​za | \ ˌin-flü-ˈen-zə \

Kids Definition of influenza

: a very contagious virus disease like a severe cold with fever

influenza

noun
in·​flu·​en·​za | \ ˌin-(ˌ)flü-ˈen-zə \

Medical Definition of influenza

1a : an acute, highly contagious, respiratory disease caused by any of three orthomyxoviruses:
(1) or influenza A : moderate to severe influenza that in humans is marked especially by sudden onset, fever, sore throat, fatigue, muscle aches, inflammation of the respiratory mucous membranes, and cough, is caused by any of several subtypes (such as H1N1, H2N2, or H3N2) of an orthomyxovirus (species Influenza A virus of the genus Influenzavirus A) infecting humans and various animals (such as birds or pigs), and may occur in seasonal epidemics or sometimes pandemics following mutation of the causative virus — see asian flu, avian influenza, bird flu, hong kong flu, spanish flu, swine flu, swine influenza
(2) or influenza B : influenza with less severe symptoms that is caused by an orthomyxovirus (species Influenza B virus of the genus Influenzavirus B) infecting only humans and especially children and that may occur in seasonal epidemics but not pandemics
(3) or influenza C : mild influenza that is often asymptomatic, is caused by an orthomyxovirus (species Influenza C virus of the genus Influenzavirus C) infecting only humans, and does not occur in epidemics or pandemics
b : any human respiratory infection of undetermined cause not used technically
2 : any of various viral diseases of domestic animals (as shipping fever of horses) marked especially by fever, respiratory symptoms, and inflammation of mucous membranes

Note: All types of influenza are commonly called “the flu.”

Other Words from influenza

influenzal \ -​zəl \ adjective
influenzal pneumonia influenzal symptoms

Keep scrolling for more

More from Merriam-Webster on influenza

Spanish Central: Translation of influenza

Nglish: Translation of influenza for Spanish Speakers

Britannica English: Translation of influenza for Arabic Speakers

Britannica.com: Encyclopedia article about influenza

Comments on influenza

What made you want to look up influenza? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

someone who never drinks alcohol

Get Word of the Day daily email!

Test Your Vocabulary

Homophone Quiz

  • three-bears-two-of-them-look-like-theyre-whispering-to-a-third-bear-who-looks-chuffed-to-be-the-center-of-attention
  • In order to judge how people felt, the senator's office hired a firm to take a ______.
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Citation

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!