British Dictionary definitions for potassium nitrate
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: KNO3Also called saltpetre, nitre
potassium nitrate A transparent, white, crystalline compound and strong oxidizing agent. It is used in gunpowder and fireworks, in making glass, and in fertilizer. Also called saltpeter. Chemical formula:KNO3. See also niter.