vi·rus noun \ˈvī-rəs\

a) an extremely small living thing that causes a disease and that spreads from one person or animal to another.

b) a disease or illness caused by a virus : a viral disease.

c) computers : a program that is designed to harm a computer by deleting data, ruining files, etc., and that can be spread secretly from one computer to another.

d) That one guy from DRAMAtical Murder who's always mistaken to be that tall guy's (Trip) twin. But they're not. Seriously. Also, he's more polite.