You may educate me on being Jewish because I think a person maybe referring to their religion or their ancestry, as in being from one of the twelve tribes?
Well, I'm not sure, Jim but maybe sweetpeach was making the analogy that there are somewhat differing belief systems under the larger umbrella of "Jewish"--sort of how there are different beleif systems (Catholic, Mormon, Baptist, etc.) under the umbrella of "Christian".
As far as your question about a person referring to their religion or ethnicity when stating they are Jewish--you're right there. It's a bit more complicated because I am Jewish by birth and ethnicity, but I do not really observe Jewish religion and would describe my spiritual beliefs in a different way.
Some people are Jewish by religion because they have converted from another religion, but they are not Jewish ethnically.