Definition of "atropine"

(toxicology, pharmacology) An alkaloid extracted from the plant deadly nightshade (Atropa belladonna) and other sources, such as the seeds of the thorn-apple. Though overdoses would be fatal it is used as a drug in medicine for its paralytic effects (e.g. in surgery to relax muscles, in dentistry to dry the mouth, in ophthalmology to dilate the pupils).