Rubber or man-made plastic fibers (such as spandex and anidex) that are naturally elastic or man-made fibers, highly twisted, heat-set, and untwisted to leave a strong crimp. Polyester has a certain degree of natural stretch and more can be given to the yarn in the processing or in the finishing of the fabric. Occasionally, polyester woven fabrics are described as stretch fabrics. Usually, stretch implies a degree of visible give in a fiber or fabric that stretches and then returns quickly to its original shape. Stretch fabrics are sometirnes described as elastic.