I usually understand God as meaning “Nature”. Some of my religious friends also throw in there the notions of “events”, " happenstance", “chance”, etc. basically a mishmash of everything we cannot explain either because of its complexity, or because we don’t have fitting models. On days I feel low, I like to think of the universe as having a purpose, a presence, and talk to it as if my voice reached the furthest stars, penetrated the densest nebulæ. It’s obvious anthropomorphism, but it makes me feel a bit better. I can only suppose it is the same for religious people.