/bel'euh don"euh/ , n.
1. Also called deadly nightshade . a poisonous plant, Atropa belladonna, of the nightshade family, having purplish-red flowers and black berries.
2. Pharm. a drug from the leaves and root of this plant, containing atropine and related alkaloids: used in medicine to check secretions and spasms, to relieve pain or dizziness, and as a cardiac and respiratory stimulant.
[ 1590-1600; bella donna lit., fair lady (so called because it is said to have been used by women to dilate the pupils of the eyes and to create an artificial pallor). See BELLE, DONNA ]