Emily Dickinson Lexicon

CAT'A-RACT, n. [L. cataracta; Gr. καταρακτης, from καταρασσω, to break or fall with violence, from ῤασσω, ῤαξω, to strike or dash.]

1. A great fall of water over a precipice; as, that of Niagara, of the Rhine, Danube, and Nile. It is a cascade upon a great scale. The tremendous cataracts of America thundering in their solitudes. – Irving.
2. In medicine and surgery, an opacity of the crystaline lens, or its capsule; a disorder in the eye, by which the pupil, which is usually black and transparent, becomes opake, blue, gray, brown, &c., by which vision is impaired or destroyed. – Encyc.