The Collaborative International Dictionary
Nitrum flammans
Nitrum \Ni"trum\, n. [L., natron. See Niter.] (Old Chem.) Niter.
Nitrum flammans [L., flaming niter] (Old Chem.), ammonium nitrate; -- probably so called because it deflagerates when suddenly heated.
Wiktionary
nitrum flammans
n. (context chemistry obsolete English) ammonium nitrate