{ Am‐mo″ni‐ac (�), Am′mo‐ni″a‐cal (�), } a. Of or pertaining to ammonia, or possessing its properties; as, an ammoniac salt; ammoniacal gas.
Ammoniacal engine, an engine in which the vapor of ammonia is used as the motive force. — Sal ammoniac [L. sal ammoniacus], the salt usually called chloride of ammonium, and formerly muriate of ammonia.