Rayon is a manufactured fiber composed of regenerated cellulose. Regenerated cellulose is a fiber in which substituents have replaced not more than 15% of the hydrogens of the hydroxyl groups of the original cellulosic material. Common sources of rayon raw cellulose material are cotton, wood pulp, various grasses, and, recently, bamboo. Rayon is produced by three methods: the viscose, cuprammonium, and solvent-spun (lyocell) processes.
Tencel, Lyocell are brand names of this type of fiber.