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, greatcoats, 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 woollen woven fabric.