Spandex is a synthetic fabric that is prized for its elasticity. Contrary to popular belief, the term "spandex" is not a brand name, and this term is used to generally refer to polyether-polyurea copolymer fabrics that have been made with a variety of production processes. The terms spandex, Lycra, and elastane are synonymous.
This fabric can stretch to 5-8 times its normal size, and it is commonly used in form-fitting consumer apparel. In most cases, pure spandex isn't used in garments, and instead, small quantities of this fabric are woven into other synthetic, semi-synthetic, or organic fibers.
Spandex fabric is used in any consumer or industrial application in which elasticity is desired. Since its inception, this type of fabric has become more and more popular, and these days, it is present in thousands of different types of garments, and it is used by consumers all over the world.
In some cases, pure spandex fabric may be used to make incredibly stretchy or fully form-fitting garments. However, this fabric is relatively expensive, which means that these types of garments are quite costly to the consumers of professionals who use them. Instead, it's much more common to see spandex fabric woven into other types of textiles.
When spandex fabric is added to cotton, for instance, this fabric becomes much more elastic, and spandex can also be used to add elasticity to traditionally rigid fabrics like polyester. Even if small amounts of this fabric are added to other textiles, these fabrics become much stretchier; since spandex can stretch up to eight times its original size, the elasticity imparted by adding this fabric to other textiles can be determined by dividing this stretching potential by the percentage in which it is included in a garment.