Acrylic yarn is a synthetic fiber made from a petroleum product called polyacrylonitrile. Its fibers are known for being lightweight, strong, and durable. It is often used as a cheaper alternative to wool and is known for being easy to care for. Acrylic yarn is used for garments and accessories that will be machine-washed or otherwise subject to rough treatment. It is also popular for baby items because it is soft and hypoallergenic.