n. A sulphate of any one of certain metals, as copper, iron, zinc, cobalt. So called on account of the glassy appearance or luster.n. Sulphuric acid; -- called also oil of vitriol. So called because first made by the distillation of green vitriol. See Sulphuric acid, under sulphuric.v. To dip in dilute sulphuric acid; to pickle.v. To vitriolize.