a white crystalline compound, NHCl, produced by the reaction of ammonia with hydrochloric acid: it is used in medicine to correct alkalosis, and also in dry cells, fertilizers, dyes, etc.; sal ammoniac
See ammonium chloride in American Heritage Dictionary 4
noun
A slightly hygroscopic, white crystalline compound, NH4Cl, used in dry cells, as a soldering flux, and as an expectorant. Also called sal ammoniac.