Oxford Music Online (Was Grove Music Online) by Deane RootCall Number: 780.3 G883d 2001 (Also available in print as New Grove Dictionary of Music and Musicians)
You will need your NetID and password to access this database from off campus. This resource is considered to be the premier English language reference resource in Music. Keep in mind that the articles that you'll find here can be lengthy, but it is a helpful tool for getting to know a particular topic and some of its related literature in the bibliographies. Also useful are works lists for selected composers. The online version also contains New Grove Dictionary of Opera as well as New Grove Dictionary of Jazz.