a. [ Gr. 'adia`batos not passable; 'a priv. + dia` through + bai`nein to go. ] (Physics) Not giving out or receiving heat. -- Ad`i*a*bat`ic*al*ly, adv. [ Webster 1913 Suppl. ]

☞The adiabatic expansion of carbon dioxide from a compressed container causes the temperature of the gas to decrease rapidly below its freezing point, resulting in the familiar carbon dioxide “snow” emitted by carbon dioxide fire extinguishers. [ PJC. ]

Adiabatic line or
curve, a curve exhibiting the variations of pressure and volume of a fluid when it expands without either receiving or giving out heat. Rankine. [ 1913 Webster ]

adj. (Physics) involving a transfer of heat. a diabatic process adiabatic [ WordNet 1.5 ]

a. [ Iso- + Gr. &unr_; to pass through. ] (Physics) Pertaining to the reception or the giving out of equal quantities of heat by a substance. Rankine. [ 1913 Webster ]

Isodiabatic lines or
Isodiabatic 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. [ 1913 Webster ]