What is a subdomain?
The most common subdomain is WWW. Most websites have WWW.name.com and the WWW is the subdomain of the second level domain: name. Subdomains are often used by tv stations. http://weather.cnn.com and http://program-name.tv-station.com. Subdomains are also frequently used for free webhosting or paid special names such as profession.com where for example a lawyer might be able to get http://LAWYERNAME.lawyer.com as his subdomain for a site. Subdomains can also have www. in front of them, e.g.: http://www.lawyername.lawyer.