noun

virus

VEYE-ruhs

noun

A microscopic infectious agent that can only reproduce inside a living host cell, sometimes causing disease.

"The flu virus mutates constantly, which is why new vaccines are needed every year."

A disease caused by such an agent.

"He was out sick with some kind of stomach virus all week."

Malicious software that spreads between computers, often damaging files or data.

"Her laptop got a virus after she opened an email attachment."

How to Use Virus

Learner’s notes

In plain EnglishA germ that causes disease, or, separately, malicious computer software that spreads and causes harm.

Common pairings

catch a virus a computer virus a virus outbreak

Word Forms

virused past tense, viruses plural, virusses plural, vira plural, viri plural, virii plural, virus plural, viruses singular

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Can you complete this real example?

The flu _____ mutates constantly, which is why new vaccines are needed every year.

Etymology

From Latin virus, meaning "poison" or "slimy liquid." The computer sense was popularized after appearing in David Gerrold's 1972 novel When HARLIE Was One.

Rhymes for virus

retrovirus

See all rhymes for virus →