Source : Webster's Revised Unabridged Dictionary (1913)

Isorropic \I`sor*rop"ic\, a. [Gr. 'iso`rropos in equipoise;
   'i`sos equal + "roph` downward inclination or momentum.]
   Of equal value.

   {Isorropic line} (in a diagram) (Geom.), the locus of all the
      points for which a specified function has a constant
      value. --Newcomb.