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.
© Webster 1913.