adiabatic /ˌeɪ.dɪəˈbæt.ɪk/adjective 2noun 1forms 1 adjective2 •Without gain or loss of heat (and thus with no change in entropy, in the quasistatic approximation).Talk of dynamic compression and adiabatic gradients didn't carry as much weight as the certainty of its conscious intent. — 2006 •Involving the slow change of the Hamiltonian of a system from its initial value to a final value.In this section we examine the limiting cases when T is very small (sudden change) and very large (adiabatic change). — 1961 noun1 •An adiabatic curve or graph formsadiabatics