Most authoritative dictionary of music available; includes over 14,000 entries on musical terms musical works, musical instruments and their history, composers, librettists, musicians, singers, and orchestras.
This subscription to Grove Music Online includes access to Oxford music reference titles, including The Oxford Companion to Music, The Encyclopedia of Popular Music and The Oxford Dictionary of Music.
Organized in 1986 to provide information about public domain music. Music and lyrics published in 1922 or earlier are in the Public Domain in the United States and therefore may be used by anyone.
Go to Scholar for more specific reference books, such as lists of music for specific instruments, biographies of composers, history and criticism of musical periods, etc.