influenza

American  

[in-floo-en-zuh] / ˌɪn fluˈɛn zə /

noun

• influenzas
  plural

1. Pathology. an acute, commonly epidemic disease, occurring in several forms, caused by numerous rapidly mutating viral strains and characterized by respiratory symptoms and general prostration.

2. Veterinary Pathology. an acute, contagious disease occurring in horses and swine, characterized by fever, depression, and catarrhal inflammations of the eyes, nasal passages, and bronchi, and caused by a virus.

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influenza British  

/ ˌɪnflʊˈɛnzə /

noun

1. Also called: grippe, flu. informal a highly contagious and often epidemic viral disease characterized by fever, prostration, muscular aches and pains, and inflammation of the respiratory passages

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influenza Scientific  

/ ĭn′flo̅o̅-ĕn′zə /

1. A highly contagious infectious disease that is caused by any of various viruses of the family Orthomyxoviridae and is characterized by fever, respiratory symptoms, fatigue, and muscle pain. It commonly occurs in epidemics, one of which killed 20 million people between 1917 and 1919.

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influenza Cultural  

1. Commonly called the flu; an acute and infectious disease of the respiratory system caused by a virus and characterized by fever, muscle pain, headache, and inflammation of the mucous membranes in the respiratory tract.

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Word History

Since ancient times, influenza has periodically swept the world. Until recently, people could not tell how this illness, which we call the flu, could spread so widely. Before people knew that organisms cause disease, they thought the stars influenced the spread of influenza. Influenza comes ultimately from the Latin word influentia, meaning “influence of the stars.” Today, however, the stars are no longer blamed for the flu. Inhaling influenza viruses causes the spread of the illness.

Other Word Forms

Derived Forms

• influenzal
  adjective
• influenzalike
  adjective
• postinfluenzal
  adjective

Inflected Forms

Nouns

• influenzas
  plural

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Etymology

Origin of influenza

1735–45; < Italian < Medieval Latin influentia influence

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Compare meaning

How does influenza compare to similar and commonly confused words? Explore the most common comparisons:

• parainfluenza vs. influenza

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Explanation

An influenza is a contagious viral infection. Influenzas tend to spread during the winter, and they're more commonly known as the flu. If you've ever wondered why this word looks so much like influence, that’s because both come from the Italian influentia. The original idea was a flowing in — of ethereal fluid from the heavens, thus affecting human destiny. We know now influenza is caused by viruses, not heavenly fluid. When you have an influenza, you're likely to vomit, have diarrhea, be exhausted, and feel terrible overall. One way to prevent influenza is by getting a flu shot.

Example Sentences

See Examples For:

influenza influenzas

She said the site used to have over 500 birds in its captive collection - but, in part due to avian influenza, today there are less than 100.

From BBC ● Oct. 17, 2026

The first request submitted to the center came from Shah and involved tracking influenza.

From Science Daily ● Sep. 15, 2026

In Ridley Scott’s simple-minded sociological study “The Dog Stars,” an influenza epidemic wiped out the majority of our squabblesome species sometime during the last decade.

From Los Angeles Times ● Aug. 28, 2026

Australian wildlife workers have launched an unprecedented effort to vaccinate wild populations of little penguins against the highly contagious H5N1 avian influenza.

From Barron's ● Aug. 20, 2026

Friday, she had to work straight through—a sixteen-hour shift—because the company was short-handed on account of an influenza epidemic.

From "A Tree Grows in Brooklyn" by Betty Smith

Human contact with nonhuman animals accounts for our influenzas as well, which usually emerge from wild aquatic birds.

From New York Times ● Jul. 25, 2023

That’s because avian and swine influenzas have caused pandemics in humans, including the 1918 flu pandemic, which was caused by a virus that originated in birds, and the 2009 swine flu pandemic.

From Scientific American ● Apr. 24, 2023

Food standards bodies advise that avian influenzas pose a very low food safety risk for UK consumers.

From BBC ● Nov. 25, 2022

“In the last 20 years we’ve had many of these pathogens emerge or re-emerge: SARS, MERS, different avian influenzas, Zika, yellow fever and of course SARS-CoV-2,” van Kerkhove said.

From Reuters ● Aug. 20, 2021

Exposure to the elements seemed to harm no one, and coughs, influenzas and rheumatics were unknown.

From My Friends at Brook Farm by John Van Der Zee Sears

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Related Words

• contagion
• curse
• epidemic
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• invasion
• outbreak
• pandemic
• scourge

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