- 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.
virus definition by Webster's New World
- Obsolete venom, as of a snake
- any of a kingdom (Virus) of prokaryotes, usually ultramicroscopic, that consist of nucleic acid, either RNA or DNA, within a case of protein: they infect animals, plants, and bacteria and reproduce only within living cells: viruses are considered as being either living organisms or inert chemicals
- a disease caused by a virus
- anything that corrupts or poisons the mind or character; evil or harmful influence
- an unauthorized, disruptive set of instructions placed in a computer program, that leaves copies of itself in other programs and disks
Origin: Classical Latin a slimy liquid, poison ; from Indo-European base an unverified form weis-, to flow (used of foul or malodorous fluids) from source ooze, weasel, Classical Greek ios, poison
virus definition by American Heritage Dictionary
noun pl. vi·rus·es
- a. Any of various simple submicroscopic parasites of plants, animals, and bacteria that often cause disease and that consist essentially of a core of RNA or DNA surrounded by a protein coat. Unable to replicate without a host cell, viruses are typically not considered living organisms.b. A disease caused by a virus.
- Something that poisons one's soul or mind: the pernicious virus of racism.
- Computer Science A computer virus.
Origin: Latin vīrus, poison.
virus - Computer Definition
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.
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.
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 Damage A 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). E-Mail Attachments Are Suspect Files attached to e-mail messages are a common way of infecting a computer when the recipient is not aware of potentially harmful file types. For example, in the Windows world, files with extensions such as .EXE, .BAT and .COM can perform any operation within the computer and should never be clicked unless the user knows they came from a valid source. See dangerous extensions and double extension. "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, quarantine, disinfect, macro virus, e-mail virus, behavior blocking, polymorphic virus, stealth virus, worm, boot virus, vandal, virus hoaxes and crypto rage.
Windows Vs. MacAlmost all Windows users install an antivirus program in their computers, while most Mac users do not, at least as of 2013. 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 Apple's official position is that it is prudent to use preventative methods. See antivirus program.
virus - Cultural Definition
See computer virus.
Microorganisms consisting of DNA and RNA molecules wrapped in a protective coating of proteins. Viruses are the most primitive form of life. They depend on other living cells for their reproduction and growth. (See under “Medicine and Health.”)
- Viruses cause many diseases. (See viral infection.)
virus - Investment & Finance Definition
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.Webster's New World Finance and Investment Dictionary Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana. Used by arrangement with John Wiley & Sons, Inc.
virus - Medical Definition
noun pl. vi·rus·es
- 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.
virus - Science Definition
- 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.
- viral viral adjective