One of the best online glossaries of Medieval Art and Architecture. For each term, users are provided with a clear definition, helpful illustration, and pronunciation guide.
This French site provides a basic overview of several Romanesque and Medieval structures located in France. The texts are brief and the images are not of the highest quality, but the site does include a useful glossary of architectural terms.
This is a collaborative website developed by Medieval Architectural Historians. The site includes an array of useful tools, including the texts of primary and secondary sources, interactive ground plans, glossaries, maps, and explanations of Christian iconography. Also accessible from this page is an index—organized according to country, city and monument—of images of several Medieval structures.