The Free On-line Dictionary of Computing (30 December 2018):

virtual host
vhost

    Most computers on the Internet have a single
   IP address; however, often via special kernel
   patches, a given computer can be made to respond to several
   IP addresses and provide different services (typically
   different Web services) on each.  Each of these different IP
   addresess (which generally each have their own hostname) act
   as if they were distinct hosts on distinct machines, even
   though they are actually all one host.  Hence, they are
   virtual hosts.  A common use is when an Internet Service
   Provider "hosts" web or other services for
   several of their customers on one computer but giving the
   appearence that they are separate servers.

   (1997-09-11)