Wordnet 3.0
NOUN (1)
1.
reflex pupillary dilation as a muscle pulls the iris outward;
occurs in response to a decrease in light or certain drugs;
The Collaborative International Dictionary of English v.0.48:
Mydriasis \My*dri"a*sis\, n. [L., fr. Gr. ?.] (Physiol. & Med.)
A long-continued or excessive dilatation of the pupil of the
eye.
[1913 Webster]
WordNet (r) 3.0 (2006):
mydriasis
n 1: reflex pupillary dilation as a muscle pulls the iris
outward; occurs in response to a decrease in light or
certain drugs