[res.in] n [ME, fr. MF resine, fr. L resina; akin to Gk rhetine pine resin] (14c) 1 a: any of various solid or semisolid amorphous fusible flammable natural organic substances that are usu. transparent or translucent and yellowish to brown, are formed esp. in plant secretions, are soluble in organic solvents (as ether) but not in water, are electrical nonconductors, and are used chiefly in varnishes, printing inks, plastics, and sizes and in medicine b: rosin
2. a: any of a large class of synthetic products that have some of the physical properties of natural resins but are different chemically and are used chiefly in plastics b: any various products made from a natural resin or a natural polymer -- res.in.ous adj
[2]resin vt res.ined ; res.in.ing (1865): to treat with resin