Cotton fabric stiffened with glue, used in bookbinding (7)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
buckram
(Other definitions for buckram that I've seen before include "Cloth stiffened with size" , "Stiffened open-weave fabric" , "Bookbinding material - cub mark (anag)" , "used in bookbinding" , "Coarse material" .)