influenza

noun
in·​flu·​en·​za | \ ˌin-(ˌ)flü-ˈen-zə How to pronounce influenza (audio) \

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."

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Other Words from influenza

influenzal \ ˌin-​(ˌ)flü-​ˈen-​zəl How to pronounce influenza (audio) \ adjective
influenzal pneumonia influenzal symptoms

Examples of influenza in a Sentence

Recent Examples on the Web During the first week after being exposed to SARS-CoV-2 or influenza virus, the symptoms that may develop are often indistinguishable. Matthew Binnicker, Forbes, 2 Sep. 2021 In January, a baby died after doctors treated the wrong condition when a test misled them to think the child had influenza A. Ellen Gabler, Milwaukee Journal Sentinel, 11 Aug. 2021 Together with Pfizer, BioNTech will start human testing for an mRNA vaccine for influenza in the third quarter. BostonGlobe.com, 9 Aug. 2021 The influenza pandemic of 1918-1919 also contributed to boarding school deaths. Brenda J. Child, Star Tribune, 29 July 2021 The nation outperformed in terms of rates of mammography screening and influenza vaccination for older adults as well as the share of adults who talked with a health care provider about nutrition, smoking and alcohol use. Tami Luhby, CNN, 4 Aug. 2021 His arrival at Rockefeller, a university dedicated to biomedical research, coincided with an international influenza outbreak. Washington Post, 25 July 2021 Even with half the U.S. vaccinated, covid-19 continues to kill people faster than guns, car crashes and influenza combined, according to a review of mortality data. Arkansas Online, 17 July 2021 These deadlier strains, responsible for three later influenza outbreaks, likely made the virus better at spreading between humans rather than birds, its natural hosts, and better at evading the immune system. Miriam Fauzia, USA TODAY, 15 July 2021

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.

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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

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Time Traveler for influenza

Time Traveler

The first known use of influenza was in 1743

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Dictionary Entries Near influenza

influential

influenza

influx

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Statistics for influenza

Last Updated

14 Sep 2021

Cite this Entry

“Influenza.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/influenza. Accessed 17 Sep. 2021.

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More Definitions for influenza

influenza

noun

English Language Learners Definition of influenza

: 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 How to pronounce influenza (audio) \

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 How to pronounce influenza (audio) \

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 How to pronounce influenza (audio) \ adjective
influenzal pneumonia influenzal symptoms

More from Merriam-Webster on influenza

Nglish: Translation of influenza for Spanish Speakers

Britannica English: Translation of influenza for Arabic Speakers

Britannica.com: Encyclopedia article about influenza

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