Broadcloth is a dense, plain woven cloth, historically made of wool. The defining characteristic of broadcloth is not its finished width but the fact that it was woven much wider (typically 50 to 75% wider than its finished width) and then heavily milled (traditionally the cloth was worked by heavy wooden trip hammers in hot soapy water) in order to shrink it to the required width. The effect of the milling process is to draw the yarns much closer together than could be achieved in the loom and allow the individual fibres of the wool to bind together in a felting process, which results in a dense, blind face cloth with a stiff drape which is highly weather-resistant, hard wearing and capable of taking a cut edge without the need for being hemmed.

The manufacturing process originates from Flanders, the type of cloth was also made in Leiden and several parts of England at the end of the medieval period. The raw material was short staple wool, carded and spun into yarn and then woven on a broad loom to produce cloth 1.75 yards wide. It was then fulled, usually in a fulling mill. When fulled, the fibres of the cloth would felt together, resulting in a smooth surface.