Source : Webster's Revised Unabridged Dictionary (1913)

Isochor \I"so*chor\, n. [Iso- + Gr. xhw`ra space.] (Physics)
   A line upon a thermodynamic diagram so drawn as to represent
   the pressures corresponding to changes of temperature when
   the volume of the gas operated on is constant. --
   {I`so*chor"ic}, a.