Appendix II at the back of the Big Book explain it quite well for me.
" With few exceptions our members find that they have tapped an unsuspected inner resource which they presently identify with their own conception of a Power greater than themselves.
Most of us think this awareness of a Power greater than ourselves is the essence of spiritual experience. Our more religious members call it “God-consciousness.” "
Unsuspected inner resource, which I now call God because I can't think of a better word. Still haven't joined any religion though, so I am not one of the more religious members.
I once detested the use of the Lords prayer in meetings. Now I have a different attitude. I quite like the sentiments the prayer expresses, and it says things I would like to say in a better way than I could come up with on my own.