Oleoresin \O`le*o*res"in\, n. [L. oleum oil + E. resin.] 1. (Chem.) A natural mixture of a terebinthinate oil and a resin. 2. (Med.) A liquid or semiliquid preparation extracted (as from capsicum, cubebs, or ginger) by means of ether, and consisting of fixed or volatile oil holding resin in solution. -- {O`le*o*res"in*ous}, a.