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 virusb : a disease or illness caused by a virusc : 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 hidden within another seemingly innocuous program and that produces copies of itself and inserts them into other programs and usually performs a malicious action (such as destroying data)
4 archaic : venom 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 of virus from the Web
Health Minister Oly Ilunga Kalenga said Friday no new cases of the deadly virus have been confirmed in the Likati zone for more than 21 days, the maximum incubation period.
The region accounts for 80 percent of the world’s primary liver cancer because of the high burden of hepatitis B virus, said Pierce Chow, an oncologist treating liver cancer patients at the National Cancer Centre Singapore, who studied SIR-Spheres.
Researchers say the knowledge will help in developing a vaccine against Lassa virus, which causes Lassa fever, a hemorrhagic fever similar to Ebola, but much more common.
Although shark attacks are rare, the virus was planted.
Dogs have no natural immunity to the flu and the virus can live up to 24 hours, so dogs can be infected just by being exposed to an area, like a dog park or grooming parlor, visited by a sick dog, Lista said.
To highlight a disconnect between other health issues and drowning, Benjamin often uses Zika virus as a familiar example for students.
Yet the virus was eventually sequenced and tamed by a small Canadian lab, said Clay Shirky, a professor at N.Y.U. Shanghai and a technology writer.
An 18-month investigation by The Associated Press during the run up to the Olympics found dangerously high levels of bacteria and viruses in Rio beaches.
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.
Origin and Etymology of virus
Latin, venom, poisonous emanation; akin to Greek ios poison, Sanskrit viṣa; in senses 1 & 3, from New Latin, from Latin
First Known Use: 1599
VIRUS Defined for Kids
Definition of virus for Students
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
Medical Definition of virus
1a: the causative agent of an infectious diseaseb: 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 virusc: a disease caused by a virus
2: an antigenic but not infective material (as vaccine lymph) obtainable from a case of an infectious disease
Seen and Heard
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