DuckCorp Dico

Found one definition

1.                 From The Jargon File (version 4.4.7, 29 Dec 2003):
                   
   
   
                   
                     
   fum
    n.
       [XEROX PARC] At PARC, often the third of the standard metasyntactic
    variables (after foo and bar). Competes with baz, which is more
       common outside PARC.