ART        

American Art 
Not just for art class; it would also be useful in English Lit and history classes to see what was happening in art during periods being studied.

Artcyclopedia       
Browse artists by name, medium,  subject,  nationality,  women artists, art movements.
Browse subjects, titles of works, museums.

Artlex Dictionary of Visual Terms
Find out about terms and words used in the art world, including "definitions of more than 3,100 terms here, along with numerous illustrations, pronunciation notes, great quotations, and links to other resources on the Web."