Woven fabrics are classified as to weave or structure according to the manner in which warp and weft cross each other. The three fundamental weaves, of which others are variations, are the plain, twill, and satin. In plain weave, also known as calico, tabby, taffeta, or homespun weaves, the weft passes over alternate warp threads, requiring two harnesses only. The relatively simple construction suits it to cheap fabrics, heavy yarns, and printed designs. Variations are produced by the use of groups of yarns, as in basket weave and monk's cloth, or by alternating fine and coarse yarns to make ribbed and corded fabrics, as the warp-ribbed Bedford cord, piqué, and dimity and the weft-ribbed poplin, rep, and grosgrain. The second primary weave, twill, shows a diagonal design made by causing weft threads to interlace two to four warp threads, moving a step to right or left on each pick and capable of variations, such as herringbone and corkscrew designs. Noted for their firm, close weave, twill fabrics include gabardine, serge, drill, and denim. Satin weave has floating or overshot warp threads on the surface which reflect light, giving a characteristic luster. When the uncrossed threads are in the weft, the weave is called sateen.
Pile fabrics have an additional set of yarns drawn over wires to form loops, and may be cut or uncut. Warp-pile fabrics include terry and plush; weft-pile, velveteen and corduroy. In double-cloth weave two cloths are woven at once, each with its warp and filling threads, and combined by interlacing some yarns or by adding a fifth set. The cloth may be made for extra warmth or strength, to permit use of a cheaper back, or to produce a different pattern or weave on each surface, e.g., steamer rugs, heavy overcoating, and machine belting. Velvet is commonly woven as a double cloth. In swivel weaving, extra shuttles with a circular motion insert filling yarns to form simple decorations, such as the dots on swiss muslin. Figure weaves are made by causing warp and weft to intersect in varied groups. Simple geometric designs may be woven on machine looms by using a cam or a dobby attachment to operate the harnesses. For curves and large figures each heddle must be separately governed. The Jacquard loom attachment permits machine weaving of the most complicated designs.