Denier: - A system of measuring the weight of a continuous filament fiber. In the United States, this measurement is used to number all manufactured fibers (both filament and staple), and silk, but excluding glass fiber. The lower the number, the finer the fiber; the higher the number, the heavier the fiber. Numerically, a denier is the equivalent to the weight in grams of 9,000 meters of continuous filament fiber.