\Ni"ter\, Nitre \Ni"tre\, n. [F. nitre, L. nitrum native
soda, natron, Gr. ?; cf. Ar. nit?n, natr?n natron. Cf.
{Natron}.]
1. (Chem.) A white crystalline semitransparent salt;
   potassium nitrate; saltpeter. See {Saltpeter}.

2. (Chem.) Native sodium carbonate; natron. [Obs.]

         For though thou wash thee with niter, and take thee
         much soap, yet thine iniquity is marked before me.
                                               --Jer. ii. 22.

{Cubic niter}, a deliquescent salt, sodium nitrate, found as
   a native incrustation, like niter, in Peru and Chili,
   whence it is known also as {Chili saltpeter}.

{Niter bush} (Bot.), a genus ({Nitraria}) of thorny shrubs
   bearing edible berries, and growing in the saline plains
   of Asia and Northern Africa.