3 links
Art and Architecture Thesaurus
getty.edu
A structured vocabulary from the Getty Trust of more than 125,000 terms for describing fine art, architecture, decorative arts, archival materials, and material culture.
California Missions Studies Terms
ca-missions.org
Illustrated glossary of terms relating to California missions and other Hispanic sites by Sasha Honig.
Glossary of Medieval Art and Architecture
pitt.edu
An illustrated and cross-referenced dictionary of mainly architectural terms from Jane Vadnal of the University of Pittsburgh.