saltpetre
/ˈsɔːltˈpiːtə(r)/( <美> saltpeter)
noun
- another term for POTASSIUM NITRATE.
词源
late Middle English: from Old French salpetre, from medieval Latin salpetra, probably representing sal petrae 'salt of rock' （i.e. found as an encrustation）. The change in the first element was due to association with SALT.