A
virus is a piece of code that requires other organisms for its reproduction. Derived from the
Latin virus (meaning roughly "poison").
- The word virus was first used for infectious disease-causing agents smaller than bacteria that reproduce with the help of a host cell; see virus (biology).
- Virus is also used metaphorically to refer to other parasitically-reproducing things like ideas (See meme). Certain types of software licence have been called "viral" due to their requirement that derivative works be released under the same licence, see GPL for the most prominent example.
- In computer science, the term virus is used for small usually malicious programs that can travel from computer to computer; see computer virus.
Despite frequent claims to the contrary, the only correct English plural of the word used in any of these senses is viruses, not virii. The "ii" is used to denote plurality in Latin words ending in "ius", not "us".
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