GC: n

CT: A computer virus, much like a flu virus, is designed to spread from host to host and has the ability to replicate itself. Similarly, in the same way that viruses cannot reproduce without a host cell, computer viruses cannot reproduce and spread without programming such as a file or document. In more technical terms, a computer virus is a type of malicious code or program written to alter the way a computer operates and that is designed to spread from one computer to another. A virus operates by inserting or attaching itself to a legitimate program or document that supports macros in order to execute its code. In the process a virus has the potential to cause unexpected or damaging effects, such as harming the system software by corrupting or destroying data.

S: Norton – https://us.norton.com/internetsecurity-malware-what-is-a-computer-virus.html (last access: 9 December 2016)

N: computer (n): 1640s, “one who calculates,” agent noun from compute (v.). Meaning “calculating machine” (of any type) is from 1897; in modern use, “programmable digital electronic computer” (1945 under this name; theoretical from 1937, as Turing machine). ENIAC (1946) usually is considered the first. Computer literacy is recorded from 1970; an attempt to establish computerate (adjective, on model of literate) in this sense in the early 1980s didn’t catch on. Computerese “the jargon of programmers” is from 1960, as are computerize and computerization.
virus (n): Late 14c., “venomous substance,” from Latin virus “poison, sap of plants, slimy liquid, a potent juice,” probably from PIE root *weis– “to melt away, to flow,” used of foul or malodorous fluids, with specialization in some languages to “poisonous fluid” (source also of 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 (in reference to venereal disease). The computer sense is from 1972.
Short form use: virus.
2. A program that propagates itself by modifying other programs to include a possibly changed copy of itself and that is executed when the infected program is invoked.
3. A virus often causes damage or annoyance and may be triggered by some event such as the occurrence of a predetermined date.
4. virus: term and definition standardized by ISO/IEC.
5. Computers and computer users are under assault by hackers like never before, but computer viruses are almost as old as electronic computers themselves. Most people use the term “computer virus” to refer to all malicious software, which we call malware. Computer Viruses are actually just one type of malware, a self-replicating programs designed to spread itself from computer to computer. A virus is, in fact, the earliest known malware invented.
6. Small but insidious piece of programming-code that attacks computer and network systems through ‘contaminated’ (infected) data files, introduced into a system via disks or internet
7. What a virus does to a computer once it has infected the computer depends on the type of virus. Typically most computer viruses will delete data, overwrite information, display messages, and add itself to other files on the computer. Almost all computer viruses only damage the data contained on the computer and do not physically harm the computer or its hardware. More sophisticated viruses like Stuxnet can cause physical damage.
8. Collocations:

• Adj.: dangerous, destructive, virulent.
• Verb + virus: be infect with; develop; carry; get; inactivate; isolate; spread; transmit.
• Virus + verb: attack sth; infect; replicate.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=computer+virus (last access: 10 December 2016). 2 to 4. TERMIUM PLUS – http://goo.gl/lrX9Ux (last access: 10 December 2016). 5. AC-https://antivirus.comodo.com/blog/computer-safety/short-history-computer-viruses/ (last access: 9 December 9 2016). 6. BD- http://www.businessdictionary.com/definition/computer-virus.html (last access: December 9 2016). 7.CH- http://www.computerhope.com/jargon/v/virus.htm (last access: 9 December 2016). 8. OCD – http://oxforddictionary.so8848.com/search1?word=virus (last access: 10 December 2016); FCB.

SYN: virus, electronic virus. (depending on field and context)

S: TERMIUM PLUS – http://goo.gl/lrX9Ux (last access: 10 December 2016)

CR: antivirus , computer science, computer worm, malware, spyware, trojan horse.