a great fall of water over a precipice, as that of Niagara, the Rhine, Danube, and Nile. The fall of the Nile now known as Chellat, was called by the ancients Cataracta. Cataracta also denoted a portcullis, from the noise it makes in falling.

a disease of the eye, in which the crystalline lens, or its capsule, becomes opaque, whereby vision is impaired or destroyed. The surgical operation of depressing a cataract is termed couching.