pharmacognosy
noun
phar·ma·cog·no·sy ˌfär-mə-ˈkäg-nə-sē 
: a branch of pharmacology dealing with medicinal substances of biological origin and especially medicinal substances obtained from plants
pharmacognostic
ˌfär-mə-ˌkäg-ˈnä-stik
adjective or pharmacognostical
ˌfär-mə-ˌkäg-ˈnä-sti-kəl
Word History
Etymology
International Scientific Vocabulary, from Greek pharmakon + -gnōsia knowledge, from gnōsis — more at gnosis
First Known Use
circa 1885, in the meaning defined above
Medical Definition
pharmacognosy
noun
phar·ma·cog·no·sy ˌfär-mə-ˈkäg-nə-sē
plural pharmacognosies
: a branch of pharmacology dealing especially with the composition, use, and development of medicinal substances of biological origin and especially medicinal substances obtained from plants