Websters new college dictionary describes it as:
1. A community or system of religious worship and ritual.

It then goes on to condense this statement into that which is outside the norms of gen acceptance.
ie, extreamist, exclusive, considered false...

I guess the word could be applied to any group when viewed by another, I prefer to be a cultic jumper since I have found no single cult to have a grasp on total truth, so I use what I can from each and leave the rest, and this is mostly how I came to be an athiest, because for myself, the parts that seemed important only served to show me that no group, nor all combined, have the slightest clue as to the reality of things.

I kind of see most of the human race as a form of cult in that the majority beleives in a supreame being in some form, afterlife, creation...

Being part of a cult and not knowing it is scary.