\Tur"peth\, n. [NL. turpethum, fr. Per. tirbid a
cathartic, turbad a purgative root. Cf. {Turbith}.] [Written
also {turbeth}, and {turbith}.]
1. (Bot.) The root of {Ipom[oe]a Turpethum}, a plant of
   Ceylon, Malabar, and Australia, formerly used in medicine
   as a purgative; -- sometimes called {vegetable turpeth}.
2. (Chem.) A heavy yellow powder, {Hg3O2SO4}, which consists
   of a basic mercuric sulphate; -- called also {turpeth
   mineral}.