Search Result for "ptosis": 
Wordnet 3.0

NOUN (1)

1. drooping of the upper eyelid caused by muscle paralysis and weakness; 



The Collaborative International Dictionary of English v.0.48:

Ptosis \Pto"sis\ (t[=o]"s[i^]s), n. [NL., fr. Gr. ptw^sis a
   falling.] (Med.)
   Drooping of the upper eyelid, produced by paralysis of its
   levator muscle.
   [1913 Webster]


WordNet (r) 3.0 (2006):

ptosis
    n 1: drooping of the upper eyelid caused by muscle paralysis and
         weakness