(1):

(n.) 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.

(2):

(n.) Same as Gelatin.