n. Medieval chemistry; the doctrines and processes of the early and medieval chemists; in particular, the supposed process, or the search for the process, by which it was hoped to transmute the baser metals into gold.n. Any magical or mysterious power or process of transmuting or transforming.n. Formerly, a mixed metal used for utensils, a modification of brass: so called because believed to have been originally formed by the art of alchemy; hence, an imitation, as alchemy was supposed to be of brass: used figuratively by Milton for a trumpet.n. Formerly also spelled alchymy.