Virtual Hosting
Virtual hosting describes a remote web server which is "host" to numerous domain names, where each domain name owner has all of the features of having a dedicated (on site) server.
Virtual hosting provides for most of the same features of a dedicated server but is located in a high speed dedicated data center costing millions of dollars.
The cost to maintain a virtual server for each site owner is a fraction of the cost of a dedicated server, with most of the benefits.