Definition and background:
Term used for a drone (a low, sustained tone) that remains steady in the bass of a composition while other voices move about above it. An organ point is also called a pedal tone, a pedal, or a drone.
For more information on the music term "Organ point" check out these other resources:
Wikipedia - Glossary of Musical Terminology
Virginia Tech Multimedia Music Dictionary
ORB -- Medieval Music Glossary