Adiabatic \Ad`i*a*bat"ic\, a. [Gr. ? not passable; 'a priv. + ? through + ? to go.]

(Physics) Not giving out or receiving heat. -- Ad`i*a*bat`ic*al*ly, adv.

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.

Source: Webster's Revised Unabridged Dictionary (1913)