Source : Webster's Revised Unabridged Dictionary (1913)

Bully \Bul"ly\, n., Bully beef \Bul"ly beef`\ [F. bouilli boiled
   meat, fr. bouillir to boil. See {Boil}, v. The word bouilli
   was formerly commonly used on the labels of canned beef.]
   Pickled or canned beef.

Source : WordNet®

bully beef
     n : beef cured or pickled in brine [syn: {corned beef}, {corn
         beef}]