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 COVID-19 vaccine booster shots appear to make a significant difference in hospitalizations from the virus, Riney said. Kristen Jordan Shamus, Detroit Free Press, 19 Jan. 2022 Or, if the results show your meningitis is from a virus, your doctor may take you off antibiotics completely and recommend recovering at home, per the CDC. Sarah Lemire, Health.com, 19 Jan. 2022 Thirty more people died from the virus since last week. Brooks Sutherland, The Enquirer, 19 Jan. 2022 The state's death toll from the virus, as tracked by the Department of Health, rose by 10, to 9,462. Andy Davis, Arkansas Online, 19 Jan. 2022 The advent of new Covid treatment pills, expected to become more widely available by midyear, carries the promise of dramatically reducing deaths from the virus. John Harwood, CNN, 16 Jan. 2022 The Chamber is strongly in favor of Alaskans getting vaccinated, and has put money behind incentive campaigns and vaccine promotion, believing protection from the virus is the best way to keep the state economy moving forward. Zachariah Hughes, Anchorage Daily News, 15 Jan. 2022 Still, children are far less likely to die from the virus. Globe Staff, BostonGlobe.com, 14 Jan. 2022 While nursing home residents account for about 1% of the state's population, the 6,986 residents who had died from the virus as of Jan. 10 represent more than 35% of all COVID-19 deaths in Indiana. Tim Evans, The Indianapolis Star, 14 Jan. 2022

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

Middle English, "pus, discharge from a sore, semen," borrowed from Latin vīrus (neuter) "venom, poisonous fluid, acrid element in a substance, secretion with medical or magical properties," going back to an Indo-European base *u̯is-/*u̯īs- "poison, venom," whence also Middle Irish "venom, poison, evil," Greek īós "poison," Tocharian A wäs and Tocharian B wase, Sanskrit viṣáṃ, Avestan viš, viša- (also vīš?); (sense 1) borrowed from German, borrowed from Latin

Note: The application of Latin vīrus to the submicroscopic infectious agents now considered viruses (rather than to any infectious agent) was apparently first made by the Dutch microbiologist Martinus Beijerinck (1851-1931) in "Ueber ein Contagium vivum fluidum als Ursache der Fleckenkrankheit der Tabaksblätter," Verhandelingen der Koninklijke Akademie van Wetenschappen te Amsterdam, Tweede Sectie, Deel VI, no. 5 (1898). Beijerinck, in studying tobacco mosaic virus, mistakenly believed that the agent was a fluid (contagium vivum fluidum, "living fluid infection") because it passed through filters capable of trapping bacteria. — The neuter gender of vīrus suggests that it was originally an s-stem; forms in text other than the nominative and accusative are perhaps found only in Lucretius. The length of the vowel in Latin, Irish, and Greek, in contrast to the short vowel in Tocharian and Indo-Iranian, has been variously accounted for. M. Mayrhofer (Etymologisches Wörterbuch des Altindoarischen) suggests that the etymon was originally a root noun, *u̯īs, *u̯is-ó-, with lengthening of the monosyllabic vowel; the daughter languages then generalized one or the other form.

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Last Updated

21 Jan 2022

Cite this Entry

“Virus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/virus. Accessed 24 Jan. 2022.

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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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