nĭtrum (noun N) = νίτρον: also called sal nitrum
* Native mineral alkali, native soda, natron; found chiefly in Media, Egypt, Thrace, and Macedonia, Plin. 31, 10, 46, § 106: flos nitri,Vitr. 7, 11, 1; and used for washing with: laveris te nitro,Vulg. Jer. 2, 22; Isid. Orig. 16, 2.—Hence
* Transf.: censuram lomentum aut nitrum esse, Cael. ap. Cic. Fam. 8, 14, 4.