The Collaborative International Dictionary of English v.0.48:
Fiber \Fi"ber\, Fibre \Fi"bre\,, n. [F. fibre, L. fibra.]
1. One of the delicate, threadlike portions of which the
tissues of plants and animals are in part constituted; as,
the fiber of flax or of muscle.
2. Any fine, slender thread, or threadlike substance; as, a
fiber of spun glass; especially, one of the slender
rootlets of a plant. [WordNet sense 1]
3. the inherent complex of attributes that determine a
person's moral and ethical actions and reactions; sinew;
strength; toughness; as, a man of real fiber. [WordNet
Syn: character, fibre.
[1913 Webster + WordNet 1.5]
Yet had no fibers in him, nor no force. --Chapman.
4. A general name for the raw material, such as cotton, flax,
hemp, etc., used in textile manufactures.
5. (Nutrition) that portion of food composed of carbohydrates
which are completely or partly indigestible, such as
cellulose or pectin; it may be in an insoluble or a
soluble form. It provides bulk to the solid waste and
stimulates peristalsis in the intestine. It is found
especially in grains, fruits, and vegetables. There is
some medical evidence which indicates that diets high in
fiber reduce the risk of colon cancer and reduce
cholesterol levels in the blood. It is also called
dietary fiber, roughage, or bulk.
6. a leatherlike material made by compressing layers of paper
or cloth. [WordNet sense 3]
Syn: fibre, vulcanized fiber.
Fiber gun, a kind of steam gun for converting, wood, straw,
etc., into fiber. The material is shut up in the gun with
steam, air, or gas at a very high pressure which is
afterward relieved suddenly by letting a lid at the muzzle
fly open, when the rapid expansion separates the fibers.
Fiber plants (Bot.), plants capable of yielding fiber
useful in the arts, as hemp, flax, ramie, agave, etc.