n. A descent of water over a steeply sloping but not perpendicular surface, as the cataracts of the Nile and the Orinoco; hence, especially in poetical use, any large waterfall, as that of the Niagara.n. Any furious rush or downpour of water.n. A disease of the eye, characterized by opacity of the lens.n. In fortification, a herse.n. A regulator for single-acting steam-engines, invented by Smeaton.n. The plungeon, a kind of cormorant: so called because of its violent downward flight in seizing its prey.n. In mech., a device for regulating the number of strokes per minute in a Cornish pumping-engine, in which the velocity of a falling weight, or a spring-weighted piston, is governed by the flow of water through a variable opening, whose cross-section can be controlled at will, so that the period of the stroke or the interval between strokes can be made longer or shorter.To form cataracts.To pour, like a cataract.