Definition of: virus

(vī′rəs) noun
1. Venom; snake poison.
2. Any virulent substance developed by morbid processes within an animal body, and capable of transmitting a specific disease, as smallpox: when inoculated in an attenuated form it is called a vaccine.
3. Any of a class of filter–passing, pathogenic agents, chiefly protein in composition but often reducible to crystalline form, and typically inert except when in contact with certain living cells: also filtrable virus.
4. An illness caused by such an agent.
5. Figuratively, a moral taint; a corrupting influence.
6. Bitterness of mind; acrimony; malice. [<L, poison, slime]