Pharmacognosy is the study of medicines derived from natural sources. The American Society of Pharmacognosy

American Society of Pharmacognosy

The American Society of Pharmacognosy is a scientific society that promotes the growth and development of pharmacognosy through presentation of research achievements and publication of meritorious research....

 defines pharmacognosy as "the study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources."
The word "pharmacognosy" is derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 words φάρμακον pharmakon (drug

Drug

A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

), and γνῶσις gnosis

Gnosis

Gnosis is the common Greek noun for knowledge . In the context of the English language gnosis generally refers to the word's meaning within the spheres of Christian mysticism, Mystery religions and Gnosticism where it signifies 'spiritual knowledge' in the sense of mystical enlightenment.-Related...

 or "knowledge

Knowledge

Knowledge is a familiarity with someone or something unknown, which can include information, facts, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject...

".