-archsuff. Ruler; leader: matriarch.[Middle English -arche, from Old French, from Late Latin -archa, from Latin -arch?s, from Greek -arkh?s, from arkhos, ruler, from arkhein, to rule.]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.-arch n combining form leader; ruler; chief: patriarch; monarch; heresiarch. [from Greek -arkh?s, from arkhein to rule; compare arch-]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014arch1 (?rt?) n. 1. a curved construction spanning an opening and usu. supporting weight from above or the sides. 2. a doorway or gateway having a curved head; archway. 3. any overhead curvature resembling an arch. 4. something bowed or curved: the arch of the foot. v.t. 5. to cover or span with an arch. 6. to form into an arch: a cat arching its back. v.i. 7. to form an arch: elms arching over the road. [1250?1300;