Definition and background:
A Percussion instrument with a deep, low sound but indeterminate pitch that is played with a large soft-headed mallet; the largest orchestral drum.A pedal operated Percussion instrument with a deep, low sound but indeterminate pitch usually found as part of a drum kit played by a single player in a srock, jazz, or other popular style group.
For more information on the music term "Bass drum" check out these other resources:
Wikipedia - Glossary of Musical Terminology
Virginia Tech Multimedia Music Dictionary
ORB -- Medieval Music Glossary