infernal stone

== English == === Etymology === Calque of Latin lapis infernalis. === Noun === infernal stone (obsolete) lapis infernalis, lunar caustic (obsolete) potassium hydroxide Synonym: caustic potash === References === “infernal”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.