ros·in / ˈräzən/ • n. resin, esp. the solid amber residue obtained after the distillation of crude turpentine oleoresin, or of naphtha extract from pine stumps. It is used in adhesives, varnishes, and inks and for treating the bows of stringed instruments.• v. (ros·ined, ros·in·ing) [tr.] rub (something, esp. the bow of a stringed instrument) with rosin.DERIVATIVES: ros·in·y adj.