(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
"Scientists confirmed the outbreak was caused by a new virus that can only replicate inside human lung cells."
a harmful or corrupting agency
"bigotry is a virus that must not be allowed to spread"
"the virus of jealousy is latent in everyone"
a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer
"a true virus cannot spread to another computer without human assistance"
A submicroscopic, non-cellular structure consisting of a core of DNA or RNA surrounded by a protein coat, that requires a living host cell to replicate, and often causes disease in the host organism; such agents are often classed as nonliving infectious particles and less often as microorganisms.
"The latest outbreak was traced back to a mutated virus that spreads rapidly through respiratory droplets when an infected person coughs."
In plain English: A virus is a tiny piece of genetic material that needs to infect a living cell to make copies of itself.
"The computer virus deleted all my important files."
Usage: Use this word specifically for microscopic infectious agents like the flu virus rather than general computer malware. It refers strictly to biological pathogens that require a living host cell to replicate and cause disease in humans, animals, or plants.
The word virus comes from Latin, where it originally meant "poison," "slime," or "venom." It entered English with this ancient sense before being first used to describe computer programs by David Gerrold in 1972.