gelatin

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A colorless or slightly yellow, transparent, brittle protein formed by boiling the specially prepared skin, bones, and connective tissue of animals and used in foods, drugs, and photographic film.
2. n. Any of various similar substances.
3. n. A jelly made with gelatin, used as a dessert or salad base.
4. n. A thin sheet made of colored gelatin used in theatrical lighting. Also called gel.

Century Dictionary and Cyclopedia

1. n. A concrete animal substance, transparent, hard, and tasteless, which swells without solution in cold water, dissolves in warm water and in acetic acid, and is insoluble in alcohol or ether. Gelatin does not exist as such in the animal tissues, but is formed by the action of boiling water on connective tissues, cartilage, ligaments, and tendons, as well as on skin, horn, fish-scales, etc. The coarser form of gelatin from hoofs, hides, etc., is called glue; that from skin and finer membranes is called size; and the purest gelatin, from the air-bladders and other membranes of fish, is called isinglass. Its leading character is the formation of a tremulous jelly when its solution in boiling water cools. A yellowish-white precipitate is thrown down from a solution of gelatin by tannin, which forms an elastic adhesive mass. Tannin has the same action also on the tissues from which gelatin is made, and this action of tannin is the foundation of the art of tanning leather. Gelatin is nearly related to the proteids. It is regarded as a nutritious food, and much used in preparing soups, jellies, etc.; but animals fed exclusively on it die with the symptoms of starvation. No chemical formula has yet been deduced for gelatin. It contains about 18.3 per cent, of nitrogen, 0.6 per cent, of sulphur, 50 of carbon, 7 of hydrogen, and 23 of oxygen. (See jelly.) In all the arts allied to photography, gelatin forms the basis of a great variety of processes. It is at present the usual vehicle for holding the sensitive salts of silver in dry plates, and for holding the sensitive bichromate of potash in all the photo-printing and photo-engraving processes. (See emulsion, carbon process (under carbon), photolithography, heliotype, and photography.) Gelatin is also used to form the copying-pad in a variety of copying processes. See hectograph.
2. n. Also called gum-dynamite.
3. Like gelatin; gelatinous.

Wiktionary

1. n. a protein derived through partial hydrolysis of the collagen extracted from animal skin, bones, cartilage, ligaments, etc.
2. n. an edible jelly made from this material
3. n. a thin, translucent membrane used as a filter for photography or for theatrical lighting effects

GNU Webster's 1913

1. n. (Chem.) Animal jelly; glutinous material obtained from animal tissues by prolonged boiling. Specifically (Physiol. Chem.), a nitrogeneous colloid, not existing as such in the animal body, but formed by the hydrating action of boiling water on the collagen of various kinds of connective tissue (as tendons, bones, ligaments, etc.). Its distinguishing character is that of dissolving in hot water, and forming a jelly on cooling. It is an important ingredient of calf's-foot jelly, isinglass, glue, etc. It is used as food, but its nutritious qualities are of a low order.

WordNet 3.0

1. n. a thin translucent membrane used over stage lights for color effects
2. n. a colorless water-soluble glutinous protein obtained from animal tissues such as bone and skin
3. n. an edible jelly (sweet or pungent) made with gelatin and used as a dessert or salad base or a coating for foods