Definition of "heresiarch" [her•e•si•arch]

• One who originates or is the chief proponent of a heresy or heretical movement. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "No, just the idea of heresiarch being female in those exact words, which appears to be original with me."
• "Elchasai's brother, Iexai, and that the heresiarch was a Jew of the time of Trajan."
• ""But tell me, my dear boy, is not this saint of yours, who preaches in secret, a kind of heresiarch?"