atropine, n. [Gr. inflexible; hence , one of the three Parcæ; 'a priv. + to turn.].
A poisonous, white, crystallizable alkaloid, extracted from the Atropa belladonna, or deadly nightshade, and the Datura Stramonium, or thorn apple. It is remarkable for its power in dilating the pupil of the eye. Called also daturine. [1913 Webster]