|adiabatic (ˌædɪəˈbætɪk, ˌeɪ-)|
|1.||(of a thermodynamic process) taking place without loss or gain of heat|
|2.||a curve or surface on a graph representing the changes in two or more characteristics (such as pressure and volume) of a system undergoing an adiabatic process|
|[C19: from Greek adiabatos not to be crossed, impassable (to heat), from |
|adiabatic (ād'ē-ə-bāt'ĭk) Pronunciation Key
Occurring without gain or loss of heat. When a gas is compressed under adiabatic conditions, its pressure increases and its temperature rises without the gain or loss of any heat. Conversely, when a gas expands under adiabatic conditions, its pressure and temperature both decrease without the gain or loss of heat. The adiabatic cooling of air as it rises in the atmosphere is the main cause of cloud formation.