Source : Webster's Revised Unabridged Dictionary (1913)

Vitriol \Vit"ri*ol\, n. [F. vitriol; cf. Pr. vitriol, vetriol,
   Sp. & Pg. vitriolo, It. vitriuolo; fr. L. vitreolus of glass,
   vitreus vitreous. See {Vitreous}.] (Chem.)
   (a) A sulphate of any one of certain metals, as copper, iron,
       zinc, cobalt. So called on account of the glassy
       appearance or luster.
   (b) Sulphuric acid; -- called also {oil of vitriol}. So
       called because first made by the distillation of green
       vitriol. See {Sulphuric acid}, under {Sulphuric}.
       [Colloq.]

   {Blue vitriol}. See under {Blue}.

   {Green vitriol}, ferrous sulphate; copperas. See under
      {Green}.

   {Oil of vitriol}, sulphuric or vitriolic acid; -- popularly
      so called because it has the consistency of oil.

   {Red vitriol}, a native sulphate of cobalt.

   {Vitriol of Mars}, ferric sulphate, a white crystalline
      substance which dissolves in water, forming a red
      solution.

   {White vitriol}, zinc sulphate, a white crystalline substance
      used in medicine and in dyeing. It is usually obtained by
      dissolving zinc in sulphuric acid, or by roasting and
      oxidizing certain zinc ores. Formerly called also {vitriol
      of zinc}.