Gosh . . . . some folks here are really down on your question n_n. It was as if your question somehow offended them. Or . . . . perhaps it was like salt in a wound. Looking at conscoiusness can be scary; we can all be a bit defensive when we are a bit frightened. The online Oxford Dictionary defines "belief" as - 'an acceptance that something exists or is true, especially one without proof'. So belief is not a word I would use regarding my experience of consciousness. That experience is one of a suite of feelings, all connected but fluid and variable. So, 'exact definition' is not easy but this works for me - ' I am a location of unexpected feelings '. No shareable proof, sorry. Afterall, I might be a butterfly dreaming I am a human being. But we seem to get by without proof. If any ask me, I say you can find proof by looking inside, at your own feelings, be your own lab, replicate what others say they have found by finding it yourself. Good luck.