biff

biff /bif/ vt.  To notify someone of incoming mail.  From
   the BSD utility `biff(1)', which was in turn named after a
   friendly golden Labrador who used to chase frisbees in the halls at
   UCB while 4.2BSD was in development.  There was a legend that it
   had a habit of barking whenever the mailman came, but the author of
   `biff' says this is not true.  No relation to {B1FF}.