Fiber
2 of the 7 encyclopedias on this shelf carry an entry for Fiber. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
or FIBRE, a filament, or thread, the minute part of either animal or vegetable substances. The scientific use of fiber is described with regard to the animal kingdom under muscle and tissue; and with regard to the vegetable kingdom, under vegetable tissue, wood, and woody fiber. In its more popular but perfectly accurate use, the word includes the hair and wool of quadrupeds, the threads of the cocoons of silk worms, etc.; the fibers of the leaves of plants and of their inner bark, the elongated cells or hairs connected with the seeds of plants, and the ordinary materials used in making cordage and textile fabrics. Mineral substances are called fibrous in structure even when it is impossible to detach the apparent fibers. The only fibrous mineral which has been used for textile fabrics is Amianthus, a variety of asbestos, but that only to a very limited extent. The animal substances used are divided into two classes -the first including hair and wool, and the second the silk of cocoons. Nearly all textile fabrics are made from the first, and the wool of the sheep is the most important division of the class. The hair of the goat, alpaca, camel, bison, and other animals is also used. The hair of most animals is, however, in general, too short to allow of its being used for textile manufacture. The vegetable kingdom yields the largest number of useful fibers, which are obtained from natural orders very different from each other. The carogenous or cryptogamous plants do not, however, afford any. From exogenous plants, fibers are obtained from the inner bark, as in the case of flax, hemp, etc., and from the hairs of the fruit, as in cotton. In endogenous plants the fiber is sometimes obtained from the fruit, as in the coconut fiber. The spathe of some palms is also used. Some of the slender palms called rattans, and the bulrush, etc., are much used, on account of their fibrous nature, for wicker-work, chair-bottoms, and similar purposes. The most valuable fibers obtained from endogenous plants come from the leaf or leaf-stalk. Among the useful vegetable fibers those of flax, hemp, and cotton have long held the first place. The principal additions, of late years, have been New Zealand flax, jute, Sunn or Sunn hemp, coir, Pita flax, Abaca or Manila hemp, Chinese grass, and some others. One of the most important uses of vegetable fiber is in the manufacture of paper.
Aiton's Encyclopedia (1910)
any fine, thread-like part of a substance, as a natural filament of silk, wool, or cotton. In the manufacture of textiles and fabrics the name is given to any animal or vegetable substance which may be spun into thread or yarn. The most important fibers are the silk of the silkworm, the wool of sheep, the hair of goats and camels, cotton, flax, and hemp. Many other plants yield fibers which are in use for special purposes and which may become more important than they are at the present time. There are two groups of natural fibers. Commercial fibers are those used by manufacturers and are therefore of commercial value. "Native" fibers are used locally and are not yet an article of commerce. Commercial fibers number less than forty, but there are hundreds of native fibers possessing qualities which might make them as valuable as some of the commercial fibers. See Agave ; Ramie ; Cotton ; Cocoanut ; Flax ; Fur ; Hemp ; Jute ; Milkweed ; Palmetto ; Pineapple Fiber ; Raffia ; Silk ; Sisal ; Grass ; Wool ; Felt