Source : Webster's Revised Unabridged Dictionary (1913)

Zoroastrian \Zo`ro*as"tri*an\, a.
   Of or pertaining to Zoroaster, or his religious system.

Zoroastrian \Zo`ro*as"tri*an\, n.
   A follower of Zoroaster; one who accepts Zoroastrianism.

Source : WordNet®

Zoroastrian
     adj : of or pertaining to Zoroaster or the religion he founded

Zoroastrian
     n : follower of Zoroaster and Zoroastrianism