It's a bass sorta, and a guitar sorta...it doesn't go as low as a regular bass, or as high as a guitar...I think it's sorta exotic :) I've seen/read about tenor guitars (four strings, don't know how it's tuned) and tenor basses (ADGC). There's also piccolo basses, and I don't really know the story on those either. There's also that thing that Elliot Sharp plays...I think it's an 8-string or something.