cataract

名词 cataract:

1. clouding of the natural lens of the eye
2. a large waterfall; violent rush of water over a precipice

1. He has developed a cataract.
   他患上了白内障。

cat.a.ract

n.（名词）
A large or high waterfall.
大瀑布或高瀑布
A great downpour; a deluge.
倾盆大雨；大洪水
Pathology Opacity of the lens or capsule of the eye, causing impairment of vision or blindness.
【病理学】 白内障：眼球晶状体或眼膜的不透明，能引起视力损伤或失明

来源：
Middle English cataracte
中古英语 cataracte
from Old French
源自 古法语
from Latin cataracta
源自 拉丁语 cataracta
from Greek katarraktôs, kataraktôs
源自 希腊语 katarraktôs, kataraktôs
probably from katarassein [to dash down] kat-, kata- [cata-] arassein [to strike]
可能源自 katarassein [冲下] kat-, kata- [前缀，表.向下，之下.] arassein [打击]