The American Heritage® Dictionary of the English Language, 4th Edition
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.
n. An alkaloid extracted from the plant deadly nightshade (Atropa belladonna) and other sources. 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).
the GNU version of the Collaborative International Dictionary of English
n. 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.
The Century Dictionary and Cyclopedia
n. See atropin.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a poisonous crystalline alkaloid extracted from the nightshade family; used as an antispasmodic and to dilate the eye pupil; also administered in large amounts as an antidote for organophosphate nerve agents or organophosphate insecticides
Word Usage
"A drug called atropine can reverse the effects if administered promptly, and pretreatment with pyridostigmine can help shield the body, by sealing off acetylcholinesterase molecules."