- an ultramicroscopic (20 to 300 nm in diameter), metabolically inert, infectious agent that replicates only within the cells of living hosts, mainly bacteria, plants, and animals: composed of an RNA or DNA core, a protein coat, and, in more complex types, a surrounding envelope.
- Informal. a viral disease.
- a corrupting influence on morals or the intellect; poison.
- a segment of self-replicating code planted illegally in a computer program, often to damage or shut down a system or network.
Origin of virus
Examples from the Web for virus
He became delirious, his heartbeat grew ragged, his blood teemed with the virus, and his lungs, liver and kidneys began to fail.The Daily Beast’s Best Longreads, Dec 8-14, 2014
December 13, 2014
By May 27, five people had succumbed to the virus and 16 more were infected.Jail Threats for Sierra Leone Ebola Victims’ Families
December 10, 2014
The fact that the virus is still alive has sustained many safety concerns, both rational and irrational, about its use.Powdered Measles Vaccine Could Be Huge for Developing World
December 2, 2014
In some ways, the rapid spread of the virus there should not be surprising.Millions Promised for Ebola Not Adding Up
November 25, 2014
Craig Spencer, the New York doctor who contracted Ebola in Guinea, was declared “cured” of the virus last week.The Sham, Scaremongering Guide to Ebola
November 20, 2014
Such an idea is as fatal to society as we know it as a virus plague.Suite Mentale
Gordon Randall Garrett
The scientists of Sator knew that the virus was virulent; in fact, too virulent for its own good.
They knew that shortly after every Nansalian died, the virus, too, would be dead.
It killed the host every time, and the virus could not live outside a living cell.
But what am I saying, A W, to you who are so free from the virus of culture?Greener Than You Think
- any of a group of submicroscopic entities consisting of a single nucleic acid chain surrounded by a protein coat and capable of replication only within the cells of living organisms: many are pathogenic
- informal a disease caused by a virus
- any corrupting or infecting influence
- computing an unauthorized program that inserts itself into a computer system and then propagates itself to other computers via networks or disks; when activated it interferes with the operation of the computer
Word Origin and History for virus
late 14c., "venomous substance," from Latin virus "poison, sap of plants, slimy liquid," probably from PIE root *weis- "to melt away, to flow," used of foul or malodorous fluids, with specialization in some languages to "poisonous fluid" (cf. Sanskrit visam "poison," visah "poisonous;" Avestan vish- "poison;" Latin viscum "sticky substance, birdlime;" Greek ios "poison," ixos "mistletoe, birdlime; Old Church Slavonic višnja "cherry;" Old Irish fi "poison;" Welsh gwy "fluid, water," gwyar "blood"). Main modern meaning "agent that causes infectious disease" first recorded 1728. The computer sense is from 1972.
- Any of a large group of submicroscopic agents that act as parasites and consist of a segment of DNA or RNA surrounded by a coat of protein. Because viruses are unable to replicate without a host cell, they are not considered living organisms in conventional taxonomic systems. Nonetheless, they are described as live when they are capable of replicating and causing disease.
- A disease caused by a virus.
- Any of various extremely small, often disease-causing agents consisting of a particle (the virion), containing a segment of RNA or DNA within a protein coat known as a capsid. Viruses are not technically considered living organisms because they are devoid of biological processes (such as metabolism and respiration) and cannot reproduce on their own but require a living cell (of a plant, animal, or bacterium) to make more viruses. Viruses reproduce first either by injecting their genetic material into the host cell or by fully entering the cell and shedding their protein coat. The genetic material may then be incorporated into the cell's own genome or remain in the cytoplasm. Eventually the viral genes instruct the cell to produce new viruses, which often cause the cell to die upon their exit. Rather than being primordial forms of life, viruses probably evolved from rogue pieces of cellular nucleic acids. The common cold, influenza, chickenpox, smallpox, measles, mumps, yellow fever, hemorrhagic fevers, and some cancers are among the diseases caused by viruses.
- Computer Science A computer program that duplicates itself in a manner that is harmful to normal computer use. Most viruses work by attaching themselves to another program. The amount of damage varies; viruses may erase all data or do nothing but reproduce themselves.
See computer virus.