What is descent of water; a cascade; a cataract; a rush of water down a precipice or steep; -- usually in the plural, sometimes in the singular; as, the falls of Niagara called?

fall — Descent of water; a cascade; a cataract; a rush of water down a precipice or steep; -- usually in the plural, sometimes in the singular; as, the falls of Niagara. (Webster's 1913.)