International Encyclopedia of Dance - Scholarly encyclopedia of just dance topics. Any word typed into this db will be related to dance. Also in hard copy.
Oxford Reference [Sources] Premiere - Performance - collection of scholarly online reference sources on the performing arts, includes the IED, above.
Duke Database list - the Duke Library's specialized databases limited to "dance" as a topic.
Encyclopedia of Esthetics - scholarly resource for the conceptual side of the arts, excellent for dance backgrounds & theory. This link places you in the Oxford Art Online database, simply select "Encyclopedia of Esthetics".
International Dictionary of Modern Dance. Lilly Reference GV1585.B46 1998
International Encyclopeda of Dance (hardcopy)