Vitriol originally referred to a group of sulfuric acid salts, particularly vitriolic acid, which were used in alchemy and early chemistry. The term comes from the Latin word "vitrum," meaning glass, due to the glassy appearance of these substances. In modern usage, "vitriol" often describes harsh, bitter criticism or abusive language directed at someone. In literature and rhetoric, vitriol can signify intense emotional expression, often used to convey strong disapproval or disdain. This figurative use highlights the destructive nature of such criticism, akin to the corrosive properties of the chemical itself.