noun: (virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein
noun: a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer
Example:A true virus cannot spread to another computer without human assistance.
noun: a harmful or corrupting agency
Example:Bigotry is a virus that must not be allowed to spread.