\I`so*di`a*bat"ic\, a. [Iso- + Gr. ? to pass
through.] (Physics)
Pertaining to the reception or the giving out of equal
quantities of heat by a substance. --Rankine.
{Isodiabatic lines} or {curves}, a pair of lines or curves
   exhibiting, on a diagram of energy, the law of variation
   of the pressure and density of a fluid, the one during the
   lowering, and the other during the raising, of its
   temperature, when the quantity of heat given out by the
   fluid during any given stage of the one process is equal
   to the quantity received during the corresponding stage of
   the other. Such lines are said to be isodiabatic with
   respect to each other. Compare {Adiabatic}.