Religion

Bible Dictionary
Concordance of proper names and terminology from the Bible.

Buddhism Glossary
Glossary of essential Buddhist terms

Glossary of Islamic Terms and Concepts
Most terms on here you would probably throw your hands up in despair and make the witness spell them on the spot, but just in case...

The Official Scientology and Dianetics Glossary
I wasn't sure how helpful this would be, until I saw some of the strange word usage. Might come in handy if you take Tom Cruise or Travolta's depo.