saltpeter

/ˌsɔltˈpitər/
noun
  1. A white, salty chemical compound (potassium nitrate) used in making gunpowder, fireworks, and as a food preservative.
    • Some old recipes for curing meat include a small amount of saltpeter.
    • Farmers once used saltpeter as a fertilizer to enrich the soil.
    • Historically, saltpeter was a key ingredient in black gunpowder.
Synonyms
What does "saltpeter" mean? | whatsthatwordmean | whatsthatwordmean