Rid′dle.
A sieve with coarse meshes, used in preparatory separation, as:— 1. The riddle of a grain-separator which removes the coarser material, such as broken heads, straw, etc., from the grain; the latter is afterward separated from the chaff by the sieves, aided by the blast; and subsequently from the cheat and cockle by the [1939] screen. Increasing fineness of meshes,—riddle, sievescreen. 2. The coarse iron sieve which separates cinders from ashes, the larger pieces of ore from the smaller, gravel from sand, etc. See sieve; sifter.3. (Wire-working.) A board with sloping pins which lean opposite ways, and between which wire is drawn in a somewhat zigzag course, to straighten it. (See wire-straightening.）
4. (Founding.) A coarse sieve (half-inch mesh), used to clean and mix the old floor-sand of the molding-shop.
5. (Hydraulic Engineering.) A kind of weir in rivers.
