The term domain name has multiple related meanings:
A name that is entered into a computer (e.g. as part of a Web site or other URL, or an e-mail address). These names are technically hostnames.
The product that Domain name registrars provide to their customers. These names are often called registered domain names.
A name which is not a hostname used for other purposes in the Domain Name System (DNS), for example the special names used by Session Initiation Protoco (VoIP) or DomainKeys.
They are sometimes colloquially (and incorrectly) referred to by marketers as "web addresses" and "domain name" and "host name" are often used interchangably.
This article will primarily discuss registered domain names. See the Domain Name Systemhostname article for further information about the most common type of domain name. article for technical discussions about general domain names and the
Source from:http://en.wikipedia.org

