Noun | 1. | mydriatic - a drug that causes the pupil of the eye to dilate; used to aid eye examinations atropine - 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 drug - a substance that is used as a medicine or narcotic |