front end

front end n.  1. An intermediary computer that does set-up
   and filtering for another (usually more powerful but less friendly)
   machine (a `back end').  2. What you're talking to when you have
   a conversation with someone who is making replies without paying
   attention.  "Look at the dancing elephants!"  "Uh-huh."  "Do
   you know what I just said?"  "Sorry, you were talking to the
   front end."  See also {fepped out}.  3. Software that provides
   an interface to another program `behind' it, which may not be as
   user-friendly.  Probably from analogy with hardware front-ends (see
   sense 1) that interfaced with mainframes.