ALCHEMIST definition: 1. a person who uses or seems to use alchemy (= attempts to to change ordinary metals into gold…. Learn more. An alchemist was a scientist in the Middle Ages who tried to discover how to change ordinary metals into gold. Collins COBUILD Advanced Learner’s Dictionary. Copyright © HarperCollins Publishers The meaning of ALCHEMY is a medieval chemical science and speculative philosophy aiming to achieve the transmutation of the base metals into gold, the discovery of a universal cure for disease, and the discovery of a means of indefinitely prolonging life. How to use alchemy in a sentence. Alchemist : Someone Who Transforms Things for the Better The History of Alchemy Definition of alchemist noun in Oxford Advanced Learner's Dictionary. Meaning , pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.