I wanted to jot down a couple ideas from the book, "The Kingdom of the Cults" by Walter Martin.
"Dr. Braden says the following: 'By the term cult I mean nothing derogatory to any group so classified. A cult, as I define it, in any religious group which differs significantly in one or more respects as to belief or practice from those religious groups which are regarded as the normative expressions of religion in our total culture.' I may add to this that a cult might also be defined as a group of people gathered about a specific person or person's misinterpretation of the Bible."
I found that helpful. It's a really good book.