he·re·si·arch (hə-rēzē-ärk′, hĕrĭ-sē-)
One who originates or is the chief proponent of a heresy or heretical movement.
[Late Latin haeresiarcha, from Late Greek hairesiarkhēs : Greek hairesis, sect; see HERESY + Greek -arkhēs, -arch.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.