Cords (binding components)

The twisted strands of fibrous material to which the sections of a book are sewn. Distinguished from "thongs (binding components)" which are the narrow strips of rawhide or processed animal skin used for the same purpose before the latter part of the 16th century, and from "tapes (binding components)" which are flat strips of closely woven cloth that perform the same function. Also distinguished from "bands (binding components)" which are the raised ridges across the spine of a bound book that indicate the location of the cords beneath the covering material.