a colourless or white crystalline compound used in gunpowders, pyrotechnics, fertilizers, and as a preservative for foods, esp as a curing salt for ham, sausages, etc (E252). Formula: KNO3
Also called: saltpetre, nitre
potassium nitrate in American English
a colorless, crystalline compound, KNO3, used in fertilizers, gunpowder, preservatives, etc., in medicine, and as a reagent and oxidizing agent in chemistry