Buckram
a coarse, heavily sized linen or cotton fabric. It is used for stiffening collars, belts, and certain portions of men's garments. A light weight buckram is used in bookbinding, and for covering carriage cushions. During the Middle Ages a costly linen fabric, used for church vestments and banners, and to a lesser extent for personal wear, was called buckram.
Volume I · Aiton’s Encyclopedia