xy·lene (z?-l?n?, z??l?n?) also xy·lol (z??lôl?, -l?l?)n.1. Any of three colorless flammable isomeric benzene derivatives, C8H10, obtained from wood and coal tar.2. A mixture of xylene isomers used as a solvent in making lacquers and rubber cement and as an aviation fuel.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.xylene (?za?li?n) n (Elements & Compounds) an aromatic hydrocarbon existing in three isomeric forms, all three being colourless flammable volatile liquids used as solvents and in the manufacture of synthetic resins, dyes, and insecticides; dimethylbenzene. Formula: C6H4(CH3)2. Also called: xylol Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014xy?lene (?za? lin) n. any of three isomeric liquids, C8H10, of the benzene series, used in aviation gasoline and organic synthesis and in making dyes. [1850?55;