A URL is the address of a resource which is retrievable using
Protocols already deployed on the
Internet. A URL defines an access
Protocol, called a "scheme", and a "scheme-dependent part", which has to provide sufficient information to locate an object using the specified scheme. In case of
HTTP URLs, the scheme is "http", and the scheme-dependent part specifies the name of the
HTTP Server as well as the path of the object on the
HTTP Server.
Even though the term URL is still in widespread use, officially there is no valid specification for it (and it is unlikely that the term will ever be revived). It has been replaced by the more general term
URI, which is the technically correct term for resource identification as used on the
WWW.