The modern american term is "hapa" - comes from Hawaii were all kinds of races blended (japanese, chinese, filipino, portugese, hawaiians and whites just for starters). Originally it was "hapa haole" which meant, roughly half-white. That's probably still the most common meaning even without the haole on the end, but it is being used for other blends more and more too.
And, FWIW, in hawaii, hapa kids are generally considered the cutest.