A film-forming substance usually in solution applied normally to warp yarn, but sometimes to weft yarns, generally before weaving. The yarn could be dipped in it or could be brushed with it. The main types are carbohydrates and their derivatives, like light rice or millet starch in handweaving. In others it could be derived from gelatin, oil, or wax. The purpose of sizing prior to weaving is to protect the yarns from abrasion in healds and reed and against each other and to strengthen them.