virus
noun
vi·rus
| \ ˈvī-rəs
\
\
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)
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
Measles deaths are rare in Israel and the United States, but both places are experiencing outbreaks of the virus. — Elizabeth Cohen, CNN, "Israeli flight attendant dies after contracting measles," 13 Aug. 2019 Further analysis revealed additional strong signals of natural selection in genes unrelated to height that code for proteins thought to protect against various types of viruses. — Michael Price, Science | AAAS, "‘Stature gene’ may reveal why these hunter-gatherers are among the world’s smallest humans," 13 Aug. 2019 The treatments, known as REGN-EB3 and mAb-114, are both monoclonal antibodies that are infused intravenously into the blood and attach themselves to the outside of the virus, preventing it from invading the patient’s cells. — Donald G. Mcneil Jr., BostonGlobe.com, "Two new Ebola treatments prove highly effective in Congo epidemic, will be offered to all patients," 12 Aug. 2019 Martin County, with 32 cases of the virus, also has had four deaths attributed to it. — Sara Marino, USA TODAY, "Florida health officials declare public health emergency for hepatitis A," 3 Aug. 2019 But the celebration of their recovery is being undermined by the latest unrelenting outbreak of the virus in Congo that has killed more than 1,800 people, nearly a third of them children, in the year since it was first detected. — NBC News, "Former U.S. Ebola patients mark 5 years since recovery while new outbreak grips Congo," 2 Aug. 2019 Ten of them were in the northern stretches of North Kivu province, where transmission of the virus has been especially difficult to control. — The Washington Post, cleveland.com, "A year on, Congo’s Ebola outbreak is only getting worse," 1 Aug. 2019 Preventing the spread of the virus also means listening to the chickens. — Jason Daley, Smithsonian, "Rare, Mosquito-Borne Virus Found in Several Chickens in Florida," 1 Aug. 2019 The foreman in this modernized CAR assembly line was the repurposed shell of the virus that causes AIDS. — Charles Graeber, WIRED, "How Scientists Built a ‘Living Drug’ to Beat Cancer," 25 July 2019These 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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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, 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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