pto.sis
n.（名词）【复数】 pto.ses[-sôz] Abnormal lowering or drooping of an organ or a part, especially a drooping of the upper eyelid caused by muscle weakness or paralysis.下垂：一个器官或器官的一部分不正常的下降或垂落，尤其指由肌肉松弛或麻痹引起的上眼睑的下垂
来源：Greek ptôsis [fall] 希腊语 ptôsis [降落] from piptein [to fall] * see pet- 源自 piptein [落下] *参见 pet-
【引伸】
pto.tic
