noun

1. a large waterfall
2. any strong flood or rush of water; deluge
3. 1. an eye disease in which the crystalline lens or its capsule becomes opaque, causing partial or total blindness
   2. the opaque area

Etymology: ME cataracte, floodgate (of heaven), cataract (of the eye) < L cataracta, a waterfall, portcullis < Gr katarhaktēs < katarhassein, to dash down < kata-, down + rhassein, to strike or ? arassein, to smite