WAN :
Stands for Wide Area Network, and usually consists of a group of Networks or LANs linked together. Quite often used for office-to-office links, and more increasingly office-to-home workers.
WAP :

Stands for Wireless Application Protocol, and is a method of sending and receiving data over the Internet via mobile phones and organisers.

Weak Password :
A password that is easily guessed or worked out, such as pet names or names of children, dates of birth and the word 'password.'
Web Bug :
A small image placed in an email or web page that alerts a spammer when a message is read.
Whitelist :
A list of reputable sources from which email, IP addresses and Domains will be accepted without being checked for spam or Viruses.
WWW :
The World Wide Web, or more affectionately 'the Web'. A method of accessing information over the Internet. The web is only part of the internet, not the internet itself.
Workstation :
A lone single user computer, usually connected to a network.
Worm :
A type of Virus that does not require a host program to work. A worm can copy itself and pass through the Internet and Email.