virus

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

Definition of virus

1a : any of a large group of submicroscopic infectious 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

Services vary, but most companies tout their ability to easily treat colds and flus, allergies, skin infections, asthma, upper respiratory infections, stomach viruses, fevers, sinus infections, headaches, irritable bowel syndrome and joint pain. Ron Hurtibise, sun-sentinel.com, "Is forced telemedicine the future of healthcare?," 28 June 2019 The emergence of viruses, especially RSV (above), as the primary cause of pneumonia highlights the growing need for new vaccines, the researchers say. Alex Fox, Science | AAAS, "Viruses—not bacteria—cause most childhood pneumonia," 27 June 2019 Distemper, an airborne virus, could have been more easily spread due to the poor conditions in the Mesa shelter compared to the county's west side shelter in Phoenix at 2500 S. 27th Ave. Rocky Baier, azcentral, "Maricopa County's Mesa animal shelter to remain under quarantine until July 1," 19 June 2019 Experts have tried to narrow it to a virus, certain mosquito species and finally the lychee fruit. Swati Gupta, CNN, "Child death toll from brain disease crosses 100 in India as parents protest," 18 June 2019 The Stuxnet computer virus, widely believed to be a joint U.S.-Israeli creation, soon disrupted thousands of Iranian centrifuges. Fox News, "AP EXPLAINS: Iran's nuclear program as 2015 deal unravels," 17 June 2019 In the 25 years since my book The Hot Zone traced the emergence of extremely lethal viruses, one of them has proved to be the most destructive: Ebola. Richard Preston, National Geographic, "What’s keeping scientists from vanquishing Ebola?," 12 June 2019 Hepatitis A is a contagious liver disease that results from exposure to the Hepatitis A virus, including from food, the FDA said. Casey Smith, Indianapolis Star, "Kroger recalls select frozen berries citing possible Hepatitis A contamination," 8 June 2019 The virus, transmitted primarily by mosquitoes, is dangerous for pregnant women because infection can increase preterm birth and miscarriage. Laura Garcia, ExpressNews.com, "San Antonio research facility gets $2 million grant to test Zika vaccine," 4 June 2019

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

6 Jul 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, infectious 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 infectious 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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