xylyl (?za?l?l) n (Chemistry) (modifier) of, containing, or denoting the group of atoms (CH3)2C6H3-, derived from xyleneCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014