Heraldic Dictionaries and Glossaries
Guide to Medieval Terms - Ed., J. S. Arkenberg
Heraldry Dictionary - Illustrated. University of Notre Dame.
Encyclopedia Mythica - An encyclopedia on Mythology, folklore and legend.
Glossary of Terms Used in Heraldry - By James Parker. Slow but well worth the wait. Illustrated. Includes an armorial.
Glossary of Heraldic Terms - An excellent Glossary by Kyl Patrick MacKay Glendrakon Herald.