virus

noun
vi·​rus | \ ˈvī-rəs \
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

With Xcel, the virus has spread into the utility industry. David Roberts, Vox, "For the first time, a major US utility has committed to 100% clean energy," 5 Dec. 2018 The unidentified person had already been ill so the diagnosis does not necessarily mean the virus is still spreading, according to Health Department spokeswoman Donna Leusner. Mike Catalini, The Seattle Times, "19th case confirmed in viral outbreak that killed 7," 25 Oct. 2018 The fact that the virus can’t spread to humans will likely lessen the impact. Jacky Wong, WSJ, "Pigs Still Can’t Fly—But WH Group Could," 24 Aug. 2018 The virus rapidly spread across the country and grew to epidemic levels, killing several young and healthy people along the way. Jessica Leigh Mattern, Country Living, "The Dog Flu Is Spreading Across the Country for the First Time In Years," 16 Aug. 2018 The virus can spread from individuals who fail to wash their hands adequately after using the restroom. Justin L. Mack, Indianapolis Star, "What you need to know: Indiana Burger King worker with Hepatitis A handled food while sick," 6 June 2018 For the virus to spread between humans, contact had to be intensive and direct. The Economist, "Lina Puthussery died of the Nipah virus on May 21st," 31 May 2018 However, the revenue potential became evident, and the virus spread across the country. Michaelle Bond, Philly.com, "Have your license plate memorized? Philly, other cities adapt to parking revolution," 29 May 2018 Ebola spreads by very close person-to-person contact and is usually only transmitted when a patient is already showing symptoms, so the virus wouldn't spread as fast as influenza or measles can. NBC News, "Where could Ebola spread?," 23 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

5 Jan 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 \

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 \

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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