/sawlt'pee"teuhr/ , n.
1. the form of potassium nitrate, KNO 3 , that occurs naturally, used in the manufacture of fireworks, fluxes, gunpowder, etc.; niter.
2. See Chile saltpeter .
Also, saltpetre .
[ 1275-1325; earlier salt peter; r. ME sal peter, salpetre salpetre, for L sal petrae salt of rock, so called because it commonly encrusts stones ]