Horner's syndrome
noun
Hor·ner's syndrome
| \ ˈhȯr-nərz-
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Medical Definition of Horner's syndrome
: a syndrome marked by sinking in of the eyeball, contraction of the pupil, drooping of the upper eyelid, and vasodilation and anhidrosis of the face, and caused by paralysis of the cervical sympathetic nerve fibers on the affected side