Twill

a term applied to any variety of textile woven in such a manner as to produce diagonal lines or ribs on the surface of the web. In plain weaving the weft threads pass under and over the warp threads in regular succession. In twill weaving a weft thread passes over one, under two, over one, under two, and so on. The second weft takes a set of warps oblique to those taken by the first weft, but passes over one, under two, exactly like the first. This process continued throughout the web makes the warp threads conspicuous in diagonal lines. The above method produces what is called two-leaf twill. If the wefts pass over one and under three warps, it results in three-leaf twill. In damask weaving eight-leaf twill is commonly employed. In satin weaving as high as twenty-four-leaf twill is employed, which gives a smooth, glossy surface. See Damask; Weaving; Satin