n. (Chem., Biochem.) A chemical substance produced by a living organism; -- a term used commonly in reference to chemical substances found in nature that have distinctive pharmacological effects. Such a substance is considered a natural product even if it can be prepared by total synthesis. [ PJC ]

n. (Chem.) That branch of chemistry which deals with the isolation, identification, structure elucidation, and study of the chemical characteristics of chemical substances produced by living organisms. [ PJC ]