Serge is a type of twill fabric that has diagonal lines or ridges on both sides, made with a two-up, two-down weave. The worsted variety is used in making military uniforms, suits, great and trench coats. Its counterpart, silk serge, is used for linings. French serge is a softer, finer variety. The word is also used for a high quality woolen woven.
From early Saxon times, most English wool ("staples") was exported. In the early sixteenth century it went mainly to a Royal monopoly at Calais (then an English possession) and was woven into cloth in France or the Low Countries. However, with the capture of Calais by the French on 7 January 1558, England began expanding its own weaving industry. This was greatly enhanced by the European Wars of Religion (Eighty Years' War, French Wars of Religion); in 1567 Calvinist refugees from the Low Countries included many skilled serge weavers, while Huguenot refugees in the early eighteenth century included many silk and linen weavers. Denim is a cotton fabric with a similar weave; its name is believed to be derived from "serge de Nîmes" after Nîmes in France.