noun
also salt·pe·tre sȯltˈpēd.ə(r), -ētə-, in rapid speech -lˈp-; ˈ ̷ ̷ˌ ̷ ̷ ̷ ̷
Etymology: alteration (influenced by salt ) (I) of earlier salpeter, from Middle English salpetre, salpeter, from Middle French salpetre, from Medieval Latin sal petrae, from Latin sal salt + petrae, gen. of petra rock, from Greek
1. : potassium nitrate
2. : chile saltpeter
3. : an efflorescence of salts sometimes formed on the surface of tobacco leaves during curing and fermentation