Source : Free On-Line Dictionary of Computing

HTTP server
     
         (Or "web server") A {server} process running
        at a {web site} which sends out {web pages} in response to
        {HTTP} requests from remote {browsers}.
     
        If one site runs more than one server they must use different
        {port numbers}.  Alternatively, several hostnames may be
        mapped to the same computer in which case they are known as
        "{virtual servers}".
     
        {Apache} and {NCSA} {HTTPd} are two popular web servers.
        There are many others including some for practically every
        {platform}.  Servers differ mostly in the "server-side"
        features they offer such as {server-side include}, and in
        their {authentication} and access control mechanisms.  All
        decent servers support {CGI} and most have some binary {API}
        as well.
     
        (1997-02-05)