(This article is about the leggings. For the full body tights, see spandex.) Tights are a kind of cloth garment, most often sheathing the body from the waist to the toe tips with a tight fit, hence the name. They come in absolute opaque, opaque, sheer and fishnet styles or a combination of them, such as the original concept of the American term pantyhose with sheer legs and opaque panty. Wearing of tights has a history going back several centuries, when they were worn by men. Today, they are worn primarily by women and girls. However, some men and boys wear them too. In recent years, they have been sometimes offered as men's fashion. Athletic tights are already considered unisex. In American English, the difference between pantyhose and tights is determined in the weight of the yarn used and the thickness to which the garment is knitted. Generally, anything up to 40 denier in the leg or overall is known as pantyhose and anything over can be classified as tights, as for example 'running tights' and 'cycling tights'. In the United Kingdom, the word "tights" is used in all cases when referring to pantyhose, and "leggings" for footless tights of heavier, normally opaque material. Tights can be sheer yet solid in colour, whereas leggings are almost or absolute opaque, not sheer. Thus the almost opaque tights are not suited as pants. There are many sub-classifications of tights or pantyhose that describe the precise construction (such as control top, seamless, support and sheer). Although most tights are mainly nylon or cotton, lycra is normally included in modern blends to improve fit. Athletic tights are absolute opaque and often footless, although they may have a "stirrup" that goes under the foot to hold the cuff down near the ankle. In both historic and modern times, the wearing of tight hosiery by males has sometimes been associated with an accompanying garment fitted over the groin of the male genitalia. In the 15th century, some men wore an elaborate and decorative cod piece to accentuate their genital endowment, and as a symbol of their virility. In modern times, male ballet dancers generally wear a dance belt beneath their tights both to provide support to the genitalia and to promote a smooth, regular appearance since tights are so skin tight as to be revealing of the contours of the male anatomy.