IPA: /nɒnˌeɪdiˈæbətɪk/
KK: /nɑːnˌeɪdiˈæbətɪk/
Referring to a process in which heat is exchanged with the surroundings, rather than being insulated from them.
In nonadiabatic systems, energy can be lost or gained due to heat transfer.
Nonadiabatic → It is formed from "non-" (meaning not) and "adiabatic" (from Greek "adiabatos", meaning impassable or not allowing heat transfer). The term "nonadiabatic" refers to processes that do allow heat transfer, contrasting with adiabatic processes where no heat is exchanged.
Think of 'not' ('non-') allowing heat transfer ('adiabatic') — that's why nonadiabatic describes processes where heat can flow.