at·ro·pine  (āt'rə-pēn', -pĭn)  n. A poisonous, bitter, crystalline alkaloid, C17H23NO3, obtained from belladonna and other related plants. It is used to dilate the pupils of the eyes and as an antispasmodic. [From New Latin Atropa, genus name of belladonna, from Greek Atropos, Atropos; see Atropos.] |