adiabatic, a. [Gr. not passable; 'a priv. + through + to go.].
Not giving out or receiving heat. [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."
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.