Dictionary between Avestan and English Translation Online
Glossary of Zoroastrian terms.
Dictionary of most common AVESTA words - Avestan is an Eastern Old Iranian language that was used to compose the hymns of the Zoroastrian holy book, the Avesta. Iranian languages are part of the Indo-Iranian Language group which includes the Indo-Aryan languages such as Sanskrit. (Wikipedia 2006).
Avestan Base Form Dictionary
Old Iranian Online - Avestan Base Form Dictionary - Jonathan Slocum and Scott L. Harvey