a colorless, crystalline compound, KNO, used in fertilizers, gunpowder, preservatives, etc., in medicine, and as a reagent and oxidizing agent in chemistry
See potassium nitrate in American Heritage Dictionary 4
noun
A transparent white crystalline compound, KNO3, used to pickle meat and in the manufacture of pyrotechnics, explosives, matches, rocket propellants, and fertilizers. Also called saltpeter.