Zoroastrianism definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
the religious system of the Persians before their conversion to Islam: it was founded by Zoroaster, and its principles, contained in the Avesta, include belief in an afterlife and in the continuous struggle of the universal spirit of good (Ormazd) with the spirit of evil (Ahriman), the good ultimately to prevail
Zoroastrianism definition by American Heritage Dictionary
The religious system founded by Zoroaster and set forth in the Avesta, teaching the worship of Ahura Mazda in the context of a universal struggle between the forces of light and of darkness.
- Zoˌro·asˈtri·an adjective & n.