So, this may be a silly question but here it is: When you say occult do you mean magical practices/beliefs? Or like any "religion" that doesn't fall into the big 6?
This is a fantastic question. Here's my take. Occult basically means hidden knowledge.
Definition:
1. supernatural, mystical, or magical beliefs, practices, or phenomena.
2. beyond the range of ordinary knowledge or experience; mysterious.
These are just a couple of ways to define it. So yes it could be magical practices and beliefs as well as the organizations that hold them. I see it as a lot of the ancient civilizations held some very interesting beliefs and rituals. One of my favs is the whole alchemy thing where people were trying to turn lead into gold. That has a science edge to it but IMO so do some of the rituals. I don't know if that helped at all as it's a broad word.