1. Antivirus: Antivirus programs and Internet security programs are used to detect or protect a computer or programmable device from malware.
2. APT: An Advanced Persistent Threat (APT) is a group with both the capability and the intent to persistently and effectively target a specific entity. More specifically, it is Internetenabled espionage using a variety of intelligence gathering techniques to access sensitive information.
3. Botnet: A botnet is a network of "zombie" computers that have been taken over by a "bot" that performs large-scale malicious acts for the creator of the botnet.
4. DoS Attack: A denial-of-service attack (DoS attack) is an attempt to make a computer resource unavailable to its intended users. Although the means to carry out, motives for, and targets of a DoS attack may vary, it generally consists of a concerted effort to prevent an Internet site or service from functioning efficiently, temporarily, or indefinitely.
5. Internet Security Suite: An internet security suite often contains malware protection as well as firewalls, anti-spyware, theft protection, and so on to more thoroughly protect users.
6. Malware: A computer user can be tricked or forced into downloading software onto a computer that is of malicious intent. Such programs are known as malware and come in many forms, such as viruses, Trojan horses, spyware, and worms. Malicious software is sometimes used to form botnets.
7. Phishing: Phishing is the act of attempting to acquire personal information such as usernames, passwords, and credit card details by masquerading as a trustworthy entity in an electronic communication, such as an email or instant message. Spear phishing is a tailored attack designed for one target.
8. Spyware: The term spyware refers to programs that surreptitiously monitor activity on a computer system and report that information to others without the user's consent.
9. Computer Virus: A computer virus is a computer program that is designed to replicate itself by copying itself into other programs stored in a computer. It may be benign or have a negative effect, such as causing a program to operate incorrectly or corrupting a computer's memory.
10. Worms: A worm is a standalone malware computer program that replicates itself in order to spread to other computers. Often, it uses a computer network to spread itself, relying on security failures on the target computer to access it.

Sources: Businessweek, PCWorld, ComputerWorld, Network World, Nasa.org