Oxford Reference Online includes:
Concise Oxford Dictionary of Art Terms
Oxford Dictionary of Art
The Grove Encyclopedia of Materials and Techniques in Art
Gale Virtual Reference Library includes:
Arts and Humanities Through the Eras
Encyclopedia of World Art (Ref 703 En19) 17 Vols. New York: McGraw-Hill, 1959-1987
Artcyclopedia - Art genres include fine art, sculpture, photography, decorative arts, folk art, architecture, and more. (http://artcyclopedia.com/)
Art and Architecture Thesaurus - An online dictionary and thesaurus of common art and architecture terms. From the Getty Museum. (http://www.getty.edu/research/conducting_research/vocabularies/aat)
Artsource - A thorough and well-organized index to art resources on the Internet. (http://www.ilpi.com/artsource/welcome.html)
Facts on File Encyclopedia of Art (Ref 703 G748)
From Abacus to Zeus: A Handbook of Art History (Ref 703 P611a)
Language of Art from A - Z (Ref 703 L139)