Maybe a silly queistion......Does dual degree in the US refer to a program with 2 different subjects (J.D./M.B.A. example) or 2 different sponsoring universities??

I think there is no general rule. As far as I know both, programs with two different subjects/degrees and with two different sponsoring universitiies, are called "dual" or "joint" degrees. In most cases however, the term "dual degree" refers to a" double" degree in the sense that you get two different types of degree (e.g. MA/MBA).

If you check the schools' websites, you will not have a problem to find out what kind of program they actually offer.

I see. Thanks for the answer. I know Columbia University offers both dual degrees and cooperates with other unis overseas, so I was a bit overwhelmed and confused with "dual degree" terminology while browsing their website. i thnk I should understand it better now. Thanks Marsha.