Fiber, also spelled fibre, is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.
They are very important in the biology of both plants and animals, for holding tissues together.
Human uses for fibers are diverse. They can be spun into filaments, string or rope, used as a component of composite materials, or matted into sheets to make products such as paper or felt.
Fibers are often used in the manufacture of other materials. Synthetic fibers can be produced very cheaply and in large amounts compared to natural fibers, but natural fibers enjoy some benefits, such as comfort, over their man-made counterparts.