pen·tane (p?n?t?n?)n. Any of three colorless, flammable isomeric hydrocarbons, C5H12, derived from petroleum and used as solvents.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.pentane (?p?nte?n) n (Elements & Compounds) an alkane hydrocarbon having three isomers, esp the isomer with a straight chain of carbon atoms (n-pentane) which is a colourless flammable liquid used as a solvent. Formula: C5H12Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014pen?tane (?p?n te?n) n. a hydrocarbon of the methane series having three liquid isomers, the most important of which, C5H12, is a highly volatile petroleum distillate used as a solvent and an anesthetic. [1875?80] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.