D defs.my
Entry 1 sense Webster, 1913

Ptosis

/(tō"sĭs)/ · Pto·sis · IPA /ˈtoʊ.sɪs/
01 n. Drooping of the upper eyelid, produced by paralysis of its levator muscle.
  1. 1.
    Drooping of the upper eyelid, produced by paralysis of its levator muscle.(Med.)