from
The Free On-line Dictionary of Computing (8 July 2008)
virtual server
<World-Wide Web> A configuration of a {World-Wide Web}
{server} that appears to {clients} as an independent server
but which is actually running on a computer that is shared by
any number of other virtual servers. Each virtual server can
be configured as an independent {website}, with its own
{hostname}, content, and security settings.
{DNS} maps the hostnames of all virtual servers on one
physical server to its {IP address}. The web server software
then uses the "Host" header in the {HTTP} request to determine
which virtual server the request was for, and then processes
the request using that virtual server's configuration.
Virtual servers allow {Internet Service Providers} to share
one computer between multiple {websites} while allowing the
owner of each website to use and administer the server as
though they had complete control.
(2003-06-23)