Flannel is a soft woven fabric, of various fineness. Flannel was originally made from carded wool or worsted yarn, but is now often made from either wool, cotton, or synthetic fiber. Vegetable flannel is made from Scots pine fibre.
Flannel may be brushed to create extra softness or remain unbrushed. Brushing is a mechanical process wherein a fine metal brush rubs the fabric to raise fine fibres from the loosely spun yarns to form a nap. Typically, flannel has a nap on either one side or both sides. If the flannel is not napped, it gains its softness through the loosely spun yarn in its woven form.
Flannel is commonly used to make tartan clothing, blankets, bed sheets, and sleepwear. The term "flannel shirt" is often used to mean any shirt with a plaid or tartan pattern.
The origin of the word is uncertain, but a Welsh origin has been suggested as fabric similar to flannel can be traced back to Wales, where it was well known as early as the 16th century. The French term flanelle was used in the late 17th century, and the German Flanell was used in the early 18th century.
Flannel has been made since the 17th century, gradually replacing the older Welsh plains, some of which were finished as "cottons" or friezes, which was the local textile product. In the 19th century, flannel was made particularly in towns such as Newtown, Montgomeryshire,Hay on Wye, and Llanidloes. The expansion of its production is closely associated with the spread of carding mills, which prepared the wool for spinning, this being the first aspect of the production of woollen cloth to be mechanised (apart from fulling). The marketing of these Welsh woollen clothes was largely controlled by the Drapers Company of Shrewsbury.