[vi.rus] n [L, venom, poisonous emanation; akin to Gk ios poison, Skt visa; in senses
2. & 4, fr. NL, fr. L] (1599) 1 archaic: venom 1
2. a: the causative agent of an infectious disease b: any of a large group of submicroscopic infective agents that are regarded either as extremely simple microorganisms or as extremely complex molecules, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, lower animals, or plants; also: filterable virus c: a disease caused by a virus
3: something that poisons the mind or soul "the force of this ~ of prejudice --V. S. Waters"
4: a computer program usu. hidden within another seemingly innocuous program that produces copies of itself and inserts them into other programs and that usu. performs a malicious action (as destroying data)