Duhaime's Law Dictionary Virus Definition: A minute parasitic microorganism. In Mosby’s Dictionary, this description is offered: “... a minute parasitic microorganism much smaller by the bacterium that, having no independent metabolic activity, may replicate only within the cell of a living plant or animal host. A virus consists of a core of nucleic acid … surrounded by a coat of antigenic protein. More than 200 viruses have been identified as capable of causing disease in humans." CITATIONS & REFERENCES Mosby’s Medical, Nursing & Allied Health Dictionary, 6th Ed. Stedman’s Medical Dictionary, 18th Ed. Categories & Topics: Duhaime & Naysmith Medical-Legal Dictionary Always looking up definitions? Save time with our search provider (modern browsers only) If you find an error or omission in Duhaime's Law Dictionary, or if you have suggestion for a legal term, we'd love to hear from you!