On the Internet or Web a domain is the name by which a computer is identified. It is mapped to a number called an IP address.
Domains can be purchased in any combination of letters, numbers, and hyphens (-) and up to between 26 and 63 characters long (not including the TLD: .com, .net, .org, etc.).
Some example domain names include:
webdesign.about.com www.about.com slashdot.org