Fabric is made of fibers that are gathered from the source, spun into threads and then they are woven or knit into the fabric. Fibers can come from many sources: plants, animal hair, insects, and crude oil. Well known plant fibers are cotton, linen, hemp, and rayons that come from bamboo, pine, spruce, and hemp. These are spun and processed into denim, t-shirtings, twills, khakis, voiles, broadcloths poplins, cotton is an especially versatile fibre and made into literally thousands of weights, textures, knits, and weaves. You can also obtain fibre from fabric by inverting the whole process but you may not get back the pure fibre.