Continuous strand of fibres grouped or twisted together and used to construct textile fabrics. Yarns are made from both natural and synthetic fibres, in filament or staple form. Filament is very long fibre, including the natural fibre silk and the synthetic fibres. Most fibres that occur in nature are fairly short, or staple, and synthetic fibres may be cut into short, uniform lengths to form staple. Spinning is the process of drawing out and twisting a mass of cleaned, prepared fibres. Filament yarns generally require less twist than do staple yarns. More twist produces stronger yarn; low twist produces softer, shinier yarn. Two or more single strands may be twisted together to form ply yarn. Knitting yarns have less twist than weaving yarns. Thread, used for sewing, is a tightly twisted ply yarn.