toluene(n = noun.substance) methylbenzene - a colorless flammable liquid obtained from petroleum or coal tar; used as a solvent for gums and lacquers and in high-octane fuels;
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. [1913 Webster]
toluene, n. a colourless aromatic liquid hydrocarbon derivative of benzene, orig. obtained from tolu, used in the manufacture of explosives etc. Also called methyl benzene.