Term: trojan

Named after the Trojan horse of Greek mythology, a trojan is a program that claims to be one thing but is, in fact, another. A trojan horse is not a virus per se, but it may carry them. For example, many people consider Kazaa, the music sharing software, to be a trojan horse, because it often carries with it a bunch of spyware. There are trojans that claim to be patches for a problem, often arriving in email, which are in fact spyware and virus installers.