Other forms: twilled; twills; twilling
Twill is a sturdy type of fabric that's woven in a distinctive diagonal pattern. You probably have twill in your closet — most jeans are made from denim twill.
Twill is often made of cotton, and the particular method used to weave it creates a durable cloth that can be used for clothes or upholstery. Your sofa may be covered in twill — one type to look for is herringbone, in which you can see a pattern of small Vs. The word twill comes from the Old English twili, "woven with double thread," and its Latin root bilix, "with a double thread."