ammonia Definition

1. (formula NH₃) a colourless pungent gas formed naturally by the bacterial decomposition of proteins, etc, and also manufactured industrially, used in liquefied form as a refrigerant, and in the form of its compounds in fertilizers and explosives.
2. An alkaline solution of ammonia in water, used as a bleach and household cleaning agent. Also called ammonium hydroxide, liquid ammonia.