Ignatius of Loy·o·la (loi-??l?), Saint 1491-1556. Spanish ecclesiastic who founded the Society of Jesus and was a leader of the Counter Reformation.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.