hub·cap (h?b?k?p?)n. A round covering over the hub of the wheel of a motor vehicle.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.hubcap (?h?b?kæp) n (Automotive Engineering) a metal cap fitting onto the hub of a wheel, esp a stainless steel or chromium-plated oneCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014hub?cap (?h?b?kæp) n. a removable cover for the center of the exposed side of an automobile wheel, covering the axle. [1900?05] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.