virus

noun
vi·​rus | \ ˈvī-rəs How to pronounce virus (audio) \
plural viruses

Definition of virus

1a : any of a large group of submicroscopic infective agents that are usually regarded as nonliving extremely complex molecules, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, animals, and plants also : filterable virus
b : a disease or illness caused by a virus
c : the causative agent of an infectious disease
2 : something that poisons the mind or soul the force of this virus of prejudice— V. S. Waters
3 : a computer program that is usually disguised as an innocuous program or file, that often produces copies of itself and inserts them into other programs, and that when run usually performs a malicious action (such as destroying data or damaging software)
4 archaic : venom sense 1

Examples of virus in a Sentence

Is the illness caused by bacteria or a virus? I think I have the virus that's going around this winter. The software checks your hard drive for viruses.
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Recent Examples on the Web

Finally, keep in mind that the herpes virus is most contagious in active sores. Hannah Orenstein, Seventeen, ""I Have a Cold Sore. Does That Mean I Have Herpes?"," 22 Feb. 2019 The virus causes fever, sore throat and blisters on hands and feet and in the mouth. Douglas Belkin, WSJ, "Colleges Try to Stop Spread of Hand, Foot and Mouth Disease," 19 Oct. 2018 This year's virus has already caused the death of a child, according to the Florida Health Department. Caroline Picard, Good Housekeeping, "No, The Flu Shot Won't Give You the Flu — But Here’s Why You Might Feel Sick Afterwards," 19 Oct. 2018 While Zika reached its peak in 2016, the virus is still out there and continues to pose risks to pregnant women and couples looking to become pregnant. Condé Nast Traveler, "12 Zika-Free Destinations to Travel to This Year," 15 Oct. 2018 These viruses can cause vomiting, rashes, nausea and, in the worst cases, death. Scott Dance, Washington Post, "Mosquitoes are at three times their normal number in Maryland this summer," 5 July 2018 The study is by no means conclusive evidence that the viruses cause Alzheimer’s. Jason Daley, Smithsonian, "Childhood Virus May Have a Role in Alzheimer’s Disease," 23 June 2018 The new findings do not prove that the viruses cause the onset or contribute to the progression of Alzheimer's disease. Melinda Wenner Moyer, Scientific American, "Harder Evidence Builds that Viruses Play a Role in Alzheimer’s," 21 June 2018 The fifth, Reston virus, has caused illness in some animals, but not in humans. Susan Scutti, CNN, "Ebola 101: Answers to your questions about causes, symptoms, transmission and treatments," 25 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'virus.' 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 virus

1599, in the meaning defined at sense 4

History and Etymology for virus

Latin, venom, poisonous emanation; akin to Greek ios poison, Sanskrit viṣa; in senses 1 & 3, from New Latin, from Latin

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Statistics for virus

Last Updated

16 Mar 2019

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Time Traveler for virus

The first known use of virus was in 1599

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More Definitions for virus

virus

noun
vi·​rus | \ ˈvī-rəs How to pronounce virus (audio) \

Kids Definition of virus

1 : a disease-causing agent that is too tiny to be seen by the ordinary microscope, that may be a living organism or may be a very special kind of protein molecule, and that can only multiply when inside the cell of an organism
2 : a disease caused by a virus
3 : a usually hidden computer program that causes harm by making copies of itself and inserting them into other programs

virus

noun
vi·​rus | \ ˈvī-rəs How to pronounce virus (audio) \

Medical Definition of virus

1a : the causative agent of an infectious disease
b : any of a large group of submicroscopic, infective agents that are usually regarded as nonliving, extremely complex molecules or sometimes as very simple microorganisms, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, animals, and plants also : filterable virus
c : a disease caused by a virus
2 : an antigenic but not infective material (as vaccine lymph) obtainable from a case of an infectious disease

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More from Merriam-Webster on virus

Rhyming Dictionary: Words that rhyme with virus

Spanish Central: Translation of virus

Nglish: Translation of virus for Spanish Speakers

Britannica English: Translation of virus for Arabic Speakers

Britannica.com: Encyclopedia article about virus

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