Source : Webster's Revised Unabridged Dictionary (1913)

Polyphase \Pol"y*phase\, a. [Poly- + phase.] (Elec.)
   Having or producing two or more phases; multiphase; as, a
   polyphase machine, a machine producing two or more pressure
   waves of electro-motive force, differing in phase; a
   polyphase current.

Source : WordNet®

polyphase
     adj : of an electrical system that uses or generates two or more
           alternating voltages of the same frequency but
           differing in phase angle [syn: {multiphase}]