de·ni·er • n. 1. / dəˈni(ə)r; ˈdenyər/ a unit of weight by which the fineness of silk, rayon, or nylon yarn is measured, equal to the weight in grams of 9000 meters of the yarn and often used to describe the thickness of hosiery: 840 denier nylon.2. / dəˈni(ə)r; dənˈyā/ hist. a French coin, equal to one twelfth of a sou, which was withdrawn from use in the 19th century.

denier twelfth of a sou XV; unit of fineness of silk yarn, etc. XIX. — AN. dener, (O)F. denier :- L. dēnārius DENARIUS.