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.
Recent Examples on the Web China’s zero-COVID policy, which aims to prevent the virus’ spread through intensive testing and lockdowns, is among the world’s strictest. Colin Lodewick, Fortune, 11 Aug. 2022 These concerns have likely risen because monkeypox can potentially spread via direct contact with objects that have been contaminated with the monkeypox virus, including fabrics, according to the CDC. Hannah Smothers, SELF, 9 Aug. 2022 Hepatitis C is caused by a virus that spreads through contact with blood from an infected person, such as by using a shared needle when injecting a drug. Neeraj G. Patel, CNN, 9 Aug. 2022 Platforms like Facebook and Twitter became hotbeds for inaccurate news about the virus, vaccines, safety guidelines, and potential treatments. Nikki Mccann Ramirez, Rolling Stone, 8 Aug. 2022 More than 200,000 children have lost a parent or primary caregiver to the virus, which has killed more than one million Americans. Mike Cason | Mcason@al.com, al, 8 Aug. 2022 No other member of their traveling party has been affected by the virus. Brian Dulik, ajc, 7 Aug. 2022 No other member of their traveling party has been affected by the virus. Brian Dulik, Chron, 6 Aug. 2022 New York on Friday became the first state to declare a state of emergency over the smallpox-like virus, which causes lesions that look like pimples or blisters, and sometimes fever, headaches, and other flu-like symptoms. Harold Maass, The Week, 3 Aug. 2022 See More

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.

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

13 Aug 2022

Cite this Entry

“Virus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/virus. Accessed 15 Aug. 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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