Listen. LISTEN, the longer I spend in the academic world, I am more convinced that describing Judaism and Jews as a religion/ethnic grope/ethnoreligion is unhelpful outside of Academic circles.
The best way to explain Judaism is using the tribe model. A lot of times Judaism is a community first and a religion second, i.e., your level of religiousness is rarely a thing that alienate you from the community.
Think of other tribes, like the Sámi, Aboriginal Australians, Māori, Yurok, Inuit ect. Each have their own unique religion, but we do not think of them as a religious group, because the tribal identity is more important, and the religion is considered part of the culture, not the opposite.
IMORTANT SIDENOTE: I am aware that many of those tribes, and other tribes have a big chunk of Christians in them, usually more Christians than those who follow the indigenous religion of the tribe. BUT for the sake of discussion, I am equating Judaism to the section that does follow the indigenous religion of the tribe.
So, despite the fact that the religious structures of Judaism is very integral to Judaism, it is partly because of the community based focus of Judaism. The most basic example is the Minyan, the fact that prayer is preferred to be done in a group. Or the fact that the Sader is meant to be a celebrated in a group. and so on.
SO, ethnoreligion is a great academic term, but for outside that world? A tribe is a much better term to explain Judaism.
