Lycra is a registered brand name for a polyurethane-based synthetic fiber that's also called spandex or elastane. The DuPont Company first developed Lycra in 1958 to replace latex rubber as a stretching agent in clothes. It's also prized for its strength and durability. Though you may think of shiny leotards and biking shorts when you think of Lycra, the elastic fabric is present in many garments.
Lycra is almost always mixed with another fabric -- even the stretchiest leotards and bathing suits are less than 40-percent Lycra mixed with cotton or polyester. Due to its ability to mold to the body, Lycra is ideal for compression garments, surgical stockings, swimwear and sportswear. It's also used to add stretch to jeans, tops, dresses and even fitted sheets.