This section is from the "A Complete Dictionary of Dry Goods" book, by George S. Cole. Also available from Amazon: A complete dictionary of dry goods and history of silk, cotton, linen, wool and other fibrous substances,: Including a full explanation of the modern processes ... together with various useful tables.
Noil. The short lengths and knots of wool taken from the long staple in the process of combing. The noils thus accumulated are used either to make felt, or are put into cloth to increase its thickness. It is the function of the combing machine now in use to separate the top, or long fiber, from the noil, or short and broken wool. Noil-yarn is also a term applied to an inferior quality of yarn spun from the combings of waste silk or wool.