A fabric made from cotton warp and soft-spun cotton weft, the fabric being subsequently raised on both sides to give an imitation of the true woollen flannel. The weave may be plain, plain with double-end warp, or twill.
Note 1: It may be woven grey and dyed or printed, or it may be woven from dyed yarns.
Note 2: Fibres other than cotton are sometimes present in the weft yarn. If these exceed 7% they are named in the description, e.g., cotton-rayon flannelette
Textile Resource (http://www.textile.org.uk)