The Collaborative International Dictionary of English v.0.48:

Bushido \Bu"shi`do`\ (b[=oo]"sh[=e]`d[=o]`), n. [Jap. bu
   military + shi knight + d[=o] way, doctrine, principle.]
   The unwritten code of moral principles regulating the actions
   of the Japanese knighthood, or Samurai; the chivalry of
   Japan.
   [1913 Webster]

         Unformulated, Bushido was and still is the animating
         spirit, the motor force of our country.  --Inazo
                                                  Nitob['e].
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Bushido
    n 1: traditional code of the Japanese samurai which stressed
         courage and loyalty and self-discipline and simple living