(resin) A thick substance that comes from plants or can be made in the laboratory from certain chemicals. Resins do not dissolve in water, and are used in plastics, varnishes, printing inks, medicine, and to make fabrics stiff.

(resin) Any of various solid or semisolid, amorphous, fusible, flammable, natural organic plant secretions that are usually transparent or translucent. It is typically colored yellowish to brown and is soluble in organic solvents (as ether) but not in water.

(resin) Polymers of high molecular weight which at some stage are capable of being molded and then hardened to form useful components; includes plant resins, oxidation or polymerization products of terpenes.

Flammable, amorphous, vegetable products of secretion or disintegration, usually formed in special cavities of plants. They are generally insoluble in water and soluble in alcohol, carbon tetrachloride, ether, or volatile oils. They are fusible and have a conchoidal fracture. They are the oxidation or polymerization products of the terpenes, and are mixtures of aromatic acids and esters. Most are soft and sticky, but harden after exposure to cold. (From Grant & Hackh's Chemical Dictionary, 5th ed & Dorland, 28th ed)