In chemistry, vitriol is an archaic name for a sulfate. The name comes from the Latin word "vitriolum" for glassy, as crystals of several metallic sulfates resemble pieces of colored glass.
Vitriol with no further qualification often means sulfuric acid.
In particular:
Black vitriol, a mixture of iron(II) sulfate and iron sulfideBlue vitriol, copper(II) sulfate pentahydrateGreen vitriol, iron(II) sulfate heptahydrateOil of vitriol, sulfuric acidRed vitriol, cobalt(II) sulfate heptahydrateRoman vitriol, copper(II) sulfate pentahydrateSpirit of vitriol, sulfuric acidSweet oil of vitriol, diethyl ether (not a sulfate)Vitriol of argile or vitriol of clay, aluminium sulfate (alum)Vitriol of Cyprus, copper(II) sulfate pentahydrateVitriol of Mars or vitriol martial, iron(III) sulfateWhite vitriol, zinc sulfate heptahydrateMany other names have the obvious meaning given that "vitriol" means "sulfate": for example, vitriol of lead is lead sulfate and so on.