Toluene \Tol"u*ene\, n. [Tolu + benzene.] (Chem.) A hydrocarbon, {C6H5.CH3}, of the aromatic series, homologous with benzene, and obtained as a light mobile colorless liquid, by distilling tolu balsam, coal tar, etc.; -- called also {methyl benzene}, {phenyl methane}, etc.