fibre Any of various materials consisting of thread-like strands. Natural fibres can be made into yarn, textiles and other products, including carpets and rope. The fibres consist of long narrow cells. Animal fibres are based on protein molecules and include wool, silk, mohair, angora, and horsehair. Vegetable fibres are based mainly on cellulose and include cotton, linen, flax, jute, sisal, and kapok. The mineral asbestos is a natural, inorganic fibre. Regenerated fibres are manufactured from natural products, modified chemically. For example, rayon is made from cellulose fibre from cotton or wood. Synthetic fibres are made from a molten or dissolved plastic resin by forcing it through fine nozzles (spinnerets). The result is a group of filaments that are wound onto bobbins. These fibres can be used as single-strand yarn, or spun to form multi-strand yarn and woven into textiles. Synthetic fibres include nylon and other polyamides, polyesters, and acrylics.

fibre A type of plant cell in which the wall has been thickened to perform a structural role. Typically, fibres are elongated sclerenchyma cells with tapered ends and have fewer cavities in the thickenings than do other types of thickened cells, though neither feature is diagnostic. Such cells can be found in the cortex, phloem, and xylem. Commercially, the term refers to a strand of fibre cells, or to the epidermal cells (epidermis) of cotton or kapok seed pods. Flax and hemp fibres come from the phloem. Sisal is extracted from highly lignified leaf fibres of Agave. The name ‘fibre’ is also given to a fine or narrow root.

fibre
1. An elongated plant cell whose walls are extensively (usually completely) thickened with lignin (see sclerenchyma). Fibres are found in the vascular tissue, usually in the xylem, where they provide structural support. The term is often used loosely to mean any kind of xylem element. The fibres of many species, e.g. flax, are of commercial importance.

2. Any of various threadlike structures in the animal body, such as a muscle fibre, a nerve fibre, a collagen fibre, or an elastic fibre.

3. (or dietary fibre; roughage) The part of food that cannot be digested and absorbed to produce energy. Dietary fibre falls into four groups: cellulose, hemicelluloses, lignins, and pectins. Highly refined foods, such as sucrose, contain no dietary fibre. Foods with a high fibre content include wholemeal cereals and flour, root vegetables, nuts, and fruit. Dietary fibre is considered by some to be helpful in the prevention of many of the diseases of Western civilization, such as diverticulosis, constipation, appendicitis, obesity, and diabetes mellitus.

fibre (fy-ber) n.
1. (in anatomy) a threadlike structure, such as a muscle cell, a nerve fibre, or a collagen fibre.

2. (in dietetics) see dietary fibre.
—fibrous (fy-brŭs) adj.

fibre †lobe of the liver XIV; thread-like body in animal or vegetable tissue XVII. — (O)F. — L. fibra.
Hence fibrous XVII; see -OUS.