nitre

From Latin nitrum, borrowed from Ancient Greek νίτρον (nítron), see natron, nitrate, nitrous, and nitric. In antiquity, nitrum refers to a range of alkaline carbonates, nitrates, or borates. Medieval alchemy evolved the term to refer to alkaline nitrates, particularly the component known in black powder or gunpowder, i.e., potassium nitrate or the nitre of French mineralogists. The English language, adopting this latter point, still uses "soda niter" to practically designate sodium nitrate, but German still refers to the mineral species nitrokalit or potassium nitrate.