Lan·franc (l?n?fr?ngk?) 1005?-1089. Italian-born English prelate and political adviser who was archbishop of Canterbury (1070-1089) and a counselor of William the Conqueror.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.Lanfranc (?lænfræ?k) n (Biography) ?1005?89, Italian ecclesiastic and scholar; archbishop of Canterbury (1070?89) and adviser to William the Conqueror. He instituted many reforms in the English ChurchCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014