Spinning is a twisting technique to form yarn from fibers. The fiber intended is drawn out, twisted, and wound onto a bobbin. A few popular fibers that are spun into yarn other than cotton, which is the most popular, are viscose, animal fibers such as wool, and synthetic polyester. Originally done by hand using a spindle whorl, starting in the 500s AD the spinning wheel became the predominant spinning tool across Asia and Europe. The spinning jenny and spinning mule, invented in the late 1700s, made mechanical spinning far more efficient than spinning by hand, and especially made cotton manufacturing one of the most important industries of the Industrial Revolution.

Yarn is a long continuous length of interlocked fibres, used in sewing, crocheting, knitting, weaving, embroidery, ropemaking, and the production of textiles. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for needlework. Yarn can be made of a number of natural or synthetic materials, and comes in a variety of colors and thicknesses. Although yarn may be dyed different colours, most yarns are solid coloured with a uniform hue.