The definition of a virus is an extremely tiny parasite that can only reproduce if it is within a living being, or anything that corrupts something else.(noun)
See virus in Webster's New World College Dictionary
Origin: L, a slimy liquid, poison < IE base *weis-, to flow (used of foul or malodorous fluids) > ooze, weasel, Gr ios, poison
See virus in American Heritage Dictionary 4
noun pl. vi·rus·es
Origin: Latin vīrus, poison.
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