Pronunciation: (in-fek'shus), [key]
1. communicable by infection, as from one person to another or from one part of the body to another: infectious diseases.
2. causing or communicating infection.
3. tending to spread from one to another: infectious laughter.
4. Law.capable of contaminating with illegality; exposing to seizure or forfeiture.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.