1.NounThe premodern and early modern study of physical changes, particularly in Europe, Arabia, and China; and chiefly in pursuit of an elixir of immortality, a universal panacea, and/or a philosopher's stone able to transmute base metals into gold, eventually developing into chemistry.
"The purpose of physical alchemy—as opposed to its various spiritual pursuits—was to treat the supposed leprosity of base metals such as lead, refining and purifying them into gold."
2.NounThe causing of any sort of mysterious sudden transmutation.
3.NounAny elaborate transformation process or algorithm.