Main Entry: adi·a·bat·ic

Pronunciation: \ˌa-dē-ə-ˈba-tik, ˌā-ˌdī-ə-\

Function: adjective

Etymology: Greek adiabatos impassable, from a- + diabatos passable, from diabainein to go across, from dia- + bainein to go — more at come

Date: 1859

: occurring without loss or gain of heat <adiabatic expansion of a gas>

— adi·a·bat·i·cal·ly \-ti-k(ə-)lē\ adverb