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

HTTP proxy server
web proxy

    A proxy server for HTTP requests.
   Typically an HTTP proxy or "web proxy" accepts HTTP requests
   containing URLs with a special prefix.  The proxy removes
   the prefix and looks for the resulting URL in its local
   cache (if it is a caching proxy).  If found, it returns the
   document immediately, otherwise it fetches it from the remote
   server, saves a copy in its cache and returns it to the
   requester.  The cache will usually have an expiry algorithm
   which flushes documents according to their age, size and
   access history.

   The purpose is to reduce the amount of data flowing over the
   proxy's Internet connection and to speed up clients' access to
   frequently requested pages, e.g. at an ISP or on a large
   company's firewall.  The proxy may also reject requests
   where the URL or content matches certain conditions.

   The Apache HTTP server can be configured to act as a proxy
   server.  Another popular software proxy is Squid.

   (2008-07-01)