This is something I wrote in a chat with a good friend of mine:
Let me give you an attempt of actually deciphering the meaning of each of those words. And by that, I mean the actual, historical-original meaning, not what the current culture of today makes out of it (like what Gnosticism/Neo-Platonism did to Jesus’ teachings).
I’m well aware you’re going to be unable to understand what follows, but I also do this for the record.
Religion: Comes from the Latin religare, to link. Religions simply denotes the relationship between human (societies) and our creators, the Elohim. A simple prayer, meditation, faith can be forms on how that relationship takes shape. Religion is strongly tied to tradition as tradition is the explanation on why we have a relationship with the Elohim to begin with.
Tradition: You can also call this the science or history of what have happened and how that got persisted over time. Basically, what has been written down or passed down orally. Kabbalah for instance means tradition.
Mysticism: The sayings and insights that people have gotten at specific instances where they have seen the creators and their technology or by telepathy. Usually this was interpreted within the context of a given religious tradition. Sometimes the creators asked to conceal certain things or not to write them down. Mysticism therefore is the concealement of religious traditional trivia that was never really acknowledged as such (because it was either hidden or too heretic). Usually initiation and hidden traditions came out of this. Sufism is simply the sum of most mystic initiation schools within the ethno-cultural religious tradition of Islam.
Church/Synagogue (or any “house of worship”): Is the assembly, the gathering place. This I think the best word to describe the institution that follows original prophetic teachings which lead to religious or religio-mystic traditions. So, in my reading, you mean a religious assembly whenever you say religion I realized.