Domain Name 

The term domain name has multiple related meanings:

• A name that identifies a computer or computers on the internet. These names appear as a component of a Web site's URL.  This type of domain name is also called a hostname.
• The product that domain name registrars provide to their customers.  These names are often called registered domain names.
• Names used for other purposes in the Domain Name System (DNS), for example the special name which follows the @ sign in an email address, or the top-level domains like .com, or the names used by the Session Initiation Protocol or DomainKeys.