* A name that identifies a computer or computers on the Internet.
These names appear as a component of a Web site's URL, e.g. en.wikipedia.org.
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 domain names like .com, or the names used by the
Session Initiation Protocol (VoIP), or DomainKeys.
* They are sometimes colloquially (and incorrectly) referred to by
marketers as "web addresses".
[From Wikipedia,
the free encyclopedia]