Source : Webster's Revised Unabridged Dictionary (1913)

Isotropic \I`so*trop"ic\, a. [Iso- + Gr. ? a turning, fr. ? to
   turn.] (Physics)
   Having the same properties in all directions; specifically,
   equally elastic in all directions.

Source : WordNet®

isotropic
     adj : invariant with respect to direction [syn: {isotropous}]
           [ant: {anisotropic}]