| Answer | Crossword Clue |
|---|---|
| petres | PETRE, saltpetre (potassium nitrate) |
| petre | saltpetre (potassium nitrate) |
| saltpetres | SALTPETRE, potassium nitrate, the chief constituent of gunpowder also SALTPETER |
| saltpeter | (US) potassium nitrate, the chief constituent of gunpowder also SALTPETRE |
| saltpeters | SALTPETER, (US) potassium nitrate, the chief constituent of gunpowder also SALTPETRE |
