NEW YORK (CNN/Money) - Phishing? Cracking? Firewall? If these terms are just so much nerdy gobbledygook to you, better wise up -- because they're describing something that could happen to you.

Cracking vs. Hacking: These two terms are often used interchangeably, but cracking is someone obtaining your password via brute-force attack, script, dictionary attack or keystroke capture. Hacking is messing with technology or systems -- not stealing anything or being destructive, just figuring out how it works.

Denial of service attack: An attack on a computer system or network that causes a loss of service to users, typically the loss of network connectivity and services by consuming the bandwidth of the victim network or overloading the resources of the victim system.

Firewall: A security system consisting of a combination of hardware and software that limits the exposure of a computer or computer network to attack from crackers.

Phishing: A Web page designed to look and sound like an official site from a trusted source, particularly one that handles credit card info, or online payments, created to make you reveal personal or credit card information.

Social engineering: A low-tech approach to fraud: talking someone into revealing information they shouldn't.

Spam: Unsolicited e-mail, harmless on its own but very very annoying, as it generally clutters up -- and may overload -- your e-mail in-box.

Spoofing: When someone receives e-mail that appears to have originated from one source when it actually was sent from another source. E-mail spoofing is often an attempt to trick the user into releasing sensitive information such as passwords. Phishing is the Web page version of this.

Virus: A computer program deliberately designed to cause damage to an infected computer system by replacing or corrupting data

Worm: A computer program that endlessly replicates itself, sometimes sending itself out via e-mail address books. May cause damage by using up so many resources in replication.

Zombie: A virus that turns your machine into a "zombie" that either sends more spam out from that machine, or more of itself -- whatever its programmed to do.