zygomatic archn. The bony arch in vertebrates that extends along the side or front of the skull beneath the eye socket and that is formed by the zygomatic bone and the zygomatic process of the temporal bone.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.zygomatic arch n 1. (Anatomy) the slender arch of bone that forms a bridge between the cheekbone and the temporal bone on each side of the skull of mammals. Also called: zygoma 2. (Zoology) the slender arch of bone that forms a bridge between the cheekbone and the temporal bone on each side of the skull of mammals. Also called: zygoma Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014zy?gomat?ic arch? n. the bony arch at the outer border of the eye socket, formed by the union of the cheekbone and the zygomatic process of the temporal bone. [1815?25] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.