virus
n. countablen. a tiny germ that gets into your body and makes you sick. You also use this word for a harmful program that secretly gets into a computer and causes damage.
n. a submicroscopic infectious agent that replicates only inside the living cells of an organism. The term is also widely applied to malicious software designed to infect and spread across computer systems.
Wash your hands so you do not catch a virus.
The school closed for two days because a stomach virus was spreading quickly among the students and staff.
Because antibiotics target bacteria, they are completely ineffective against a virus, forcing doctors to rely on vaccines, antiviral medications, or the patient's own immune system.
From Middle English virus, from Latin vīrus (“poison, slime, venom”), via rhotacism from Proto-Italic weizos, from Proto-Indo-European wisós (“fluidity, slime, poison”). First use in the computer context by David Gerrold in his 1972 book When HARLIE Was One.
Often used colloquially to refer to the illness caused by the infectious agent rather than the agent itself.