\Zo`ro*as"tri*an*ism\, n.
The religious system of Zoroaster, the legislator and prophet
of the ancient Persians, which was the national faith of
Persia; mazdeism. The system presupposes a good spirit
(Ormuzd) and an opposing evil spirit (Ahriman). Cf. {Fire
worship}, under {Fire}, and {Parsee}.