A class name for various genera of fibers (including filaments) produced from fiber forming substances which may be polymers synthesized from chemical compounds (acrylic, nylon, polyester, polyethylene), modified, or transformed natural polymers (cellulose-based fibers like acetate and rayon) and minerals, e.g. glasses. The term manufactured usually refers to chemically produced fibers to distinguish them from truly natural fibers such as cotton, wool, silk, and flax.