A program that modifies other programs or databases in unauthorised ways especially one that propagates a virus or Trojan horse. See also worm, mockingbird. The analogy, of course, is with phage viruses in biology. [Jargon File]

In addition suitable contents:
[ = ] [ ag ] [ al ] [ am ] [ an ] [ analog ] [ ar ] [ arc ] [ arg ] [ as ] [ at ] [ au ] [ b ] [ ba ] [ base ] [ bi ] [ ch ] [ ci ] [ ck ] [ co ] [ data ] [ database ] [ du ] [ ec ] [ ed ] [ ee ] [ er ] [ es ] [ fi ] [ file ] [ ga ] [ gate ] [ gb ] [ ge ] [ gr ] [ gy ] [ h ] [ hat ] [ hr ] [ id ] [ ie ] [ il ] [ in ] [ io ] [ ir ] [ is ] [ it ] [ J ] [ Jargon File ] [ ki ] [ Lex ] [ ls ] [ ly ] [ mo ] [ mockingbird ] [ mod ] [ module ] [ ms ] [ na ] [ ne ] [ ng ] [ op ] [ pa ] [ pe ] [ ph ] [ pr ] [ program ] [ query ] [ rc ] [ re ] [ ro ] [ ru ] [ S ] [ se ] [ so ] [ spec ] [ T ] [ th ] [ Trojan horse ] [ us ] [ vi ] [ virus ] [ viruses ] [ worm ]