A domain name is a case-insensitive string of letters, numbers, and hyphens that is used to define the location of a website. Domain names are used as pointers to IP addresses. Domain names are typically arranged hierarchically, with the more generic names on the right. For example in my domain name:
There are three parts (separated by periods). The most specific is my site name "webdesign". This is followed by the company name "about", and finally the top-level domain name (TLD) "com".
Most website domain names start with "www" because they were placed on the www or Web machine for their company. A company might have other domain names that are not websites, such as FTP sites or email servers and older technology like gopher.
Some example domain names include:
webdesign.about.com www.about.com slashdot.org