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:
Many other names have the obvious meaning given that "vitriol" means "sulfate": for example, vitriol of lead is lead sulfate and so on.