Virus meaning

vīrəs
Frequency:
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.
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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.
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The definition of a virus is an extremely tiny parasite that can only reproduce if it is within a living being, or anything that corrupts something else.

An example of a virus is HIV.

An example of a virus is a set of harmful instructions which is placed on a computer to disrupt the operation of the computer.

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Any of various submicroscopic agents that infect living organisms, often causing disease, and that consist of a single or double strand of RNA or DNA surrounded by a protein coat. Unable to replicate without a host cell, viruses are typically not considered living organisms.
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A disease caused by a virus.
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Software used to infect a computer. After the virus code is written, it is buried within an existing program. Once that program is executed, the virus code is activated and attaches copies of itself to other programs in the computer and other computers in the network. Infected programs continue to propagate the virus, which is how it spreads.The effect of the virus may be a simple prank that pops up a message on screen out of the blue, or it may destroy programs and data right away or on a certain date. For example, the famous Michelangelo virus contaminated the machine on Michelangelo's birthday.Viruses Must Be Run to Do DamageA virus is a self-contained program that attaches itself to an existing application in a manner that causes it to be executed when the application is run. Macro viruses are similar. The virus code has replaced some or all of the macro commands. Likewise, it is in the execution of the macro that the damage is done (see macro language)."In the Wild"The term "computer virus" was coined in the early 1980s, supposedly after a graduate student presented the concept of a program that could "infect" other programs. Since then, more than a million viruses have been defined. However, the bulk of the infections are from only a few hundred active variants, said to be "in the wild."Since 1993, the WildList Organization has been keeping track of virus attacks around the world. For more information, visit www.wildlist.org. For a sampling of different virus infections, see virus examples. See in the wild, dangerous extensions, quarantine, disinfect, macro virus, email virus, behavior detection, polymorphic virus, stealth virus, worm, boot virus, vandal, virus hoaxes and crypto rage.Virus TheoryJohn von Neumann theorized that a computer program could replicate itself in his 1949 paper "Theory and Organization of Complicated Automata," and computer scientist Fred Cohen described the logic for several types of viruses in his 1984 paper "Computer Viruses - Theory and Experiments." See von Neumann architecture.Windows vs. MacAlmost all Windows users install an antivirus program in their computers, while many Mac users do not. Windows computers are attacked constantly, because they make up the huge majority of personal computers and are therefore the low-hanging fruit. In addition, the Mac is a Unix-based machine, and the Unix architecture separates the operating system from the applications, which makes it harder to crack, although not impossible. While the majority of Mac users do not use antivirus software, there have indeed been successful virus attacks against Macs, and Mac users are installing antivirus more than they have in the past. See antivirus program.
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A destructive computer program that typically is passed around unknow-ingly via infected e‑mail messages. Viruses cause problems for corporate networks and individuals’ computers.
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A type of intrusive malware that replicates itself and inserts copies of itself in legitimate programs, where it carries out unwanted and often damaging operations. Viruses initially were spread through infected floppy disks, which users frequently exchanged to share data and software. The most common contemporary methods of propagation are through attachments to Internet e-mail and programs downloaded from Websites. Viruses can be prevented if users open attachments only from trusted correspon dents, visit only trusted websites, and purchase anti-virus software that they keep current. The term virus, in the contemporary context, was first used by Fred Cohen in his paper "Experiments with Computer Viruses" (1984). According to Cohen, the term was coined by Len Adleman; however, the term was in common usage long before.The science fiction novel When HARLIE was One (1972), by David Gerrold, describes a computer program named VIRUS, which could be countered by a program named VACCINE. See also malware, spyware, Trojan horse, and worm.
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Can be a harmful, self-replicating program usually hidden in another piece of computer code, such as an email message. However, some virus infections are purely host-based, so they do their “black magic” only locally. Because viruses replicate across a network in a variety of ways, they can cause Denial of Service (DoS) attacks in which the victim is not specifically targeted but is an unlucky host. Depending on the type of virus, the DoS can be hardly noticeable—or it can cause a major ­disaster. A security expert and content editor for Symantec’s online magazine SecurityFocus notes that as of April 2005, Windows users had experienced more than 140,000 virus attacks, in contrast to the Macintosh Apple users who had experienced none. Some security experts maintain that Apple’s freedom from viruses is caused by a lack of critical mass, but Symantec’s expert thinks it is a combination of Apple’s OS X operating system and its three-tiered user-privilege system—(i) user, (ii) GUI superuser, and (iii) root—that is disabled by default. Perhaps that is why, says the Symantec security professional, that Apple experiences a 70% year-over-year growth in ­revenues. Goldberg, I. Glossary of Information Warfare Terms. [Online, October 27, 2003.] Institute for the Advanced Study of Information Warfare. http://www.psycom.net/iwar.2 .html; Martin, K. Apple’s Big Virus. [Online, April 21, 2005.] Reg SETI Group Website. http:// www.theregister.co.uk/2005/04/21/apples_big_virus/; TechTarget. Denial of Service. [Online, May 16, 2001.] TechTarget Website. http://searchsecurity.techtarget.com/sDefinition/0,,sid14_ gci213591,00.htm.
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(archaic) Venom, as produced by a poisonous animal etc.
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A type of microscopic agent that causes an infectious disease; the disease so caused.

He caught a virus and had to stay home from school.

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(pathology, microbiology, virology) A submicroscopic infectious organism, now understood to be a non-cellular structure consisting of a core of DNA or RNA surrounded by a protein coat. It requires a living cell to replicate, and often causes disease in the host organism.
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(computing) A computer virus.
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The taxonomic kingdom made up of the viruses.
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A computer program or series of commands that can replicate itself and that spreads by inserting copies of itself into other files or programs which users later transfer to other computers. Viruses usually have a harmful effect, as in erasing all the data on a disk.
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A harmful or destructive influence.

The pernicious virus of racism.

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Venom, as of a snake.
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Anything that corrupts or poisons the mind or character; evil or harmful influence.
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An unauthorized, disruptive set of instructions placed in a computer program, that leaves copies of itself in other programs and disks.
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Origin of virus

  • Latin vīrus poison

    From American Heritage Dictionary of the English Language, 5th Edition

  • From Latin virus (“poison, slime, venom"). First use in the computer context by David Gerrold in his 1972 book When HARLIE Was One.

    From Wiktionary

  • Latin virus (“venom or poison").

    From Wiktionary