isodiabatic

from The Century Dictionary.

• noun A curve which represents the isothermal changes of pressure and volume of a substance while the same quantity of heat is being transferred to it or from it.
• Pertaining to the transmission to or from a body of equal quantities of heat.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Physics) Pertaining to the reception or the giving out of equal quantities of heat by a substance.
• adjective 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Pertaining to the reception or the giving out of equal quantities of heat by a substance.