Textile fibers, threads, yarns and fabrics are measured in a multiplicity of units.
The linear density of a fiber is commonly measured in units of denier or tex. Traditional units include worsted count, cotton count and yield. Tex is more likely to be used in Canada and Continental Europe, while denier remains more common in the United States and United Kingdom. The International System of Units uses kilogram per metre for linear densities; in some contexts, the tex unit is used instead.
Denier /ˈdɛnjər/ or den (abbreviated D), a unit of measure for the linear mass density of fibers, is the mass in grams per 9000 meters of the fiber. The denier is based on a natural reference: a single strand of silk is approximately one denier; a 9000-meter strand of silk weighs about one gram. The term denier comes from the French denier, a coin of small value (worth 1⁄12 sou). Applied to yarn, a denier was held to be equal in weight to 1⁄24 ounce (1.2 g). Microdenier describes filaments that weigh less than 1 g per 9000 m.
There is a difference between filament and total measurements in deniers. Both are defined as above; but the first relates to a single filament of fiber (commonly called denier per filament (DPF)), whereas the second relates to a yarn.