What’s the Difference Between Malware, Trojan, Virus, and Worm?
There are a lot of heavily technical terms that get used around computer security. Many of them can be a bit hard to explain in a simple manner, so they often get used incorrectly. One of the most frequently (and painfully) misused groups is the terms that differentiate malware from other types of vulnerabilities and [...]
http://www.intego.com/mac-security-blog/whats-the-difference-between-malware-trojan-virus-and-worm/