What is the meaning of Alchemy?

The 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 causing of any sort of mysterious sudden transmutation.

Any elaborate transformation process or algorithm.

Source: wiktionary.org