undercover:
I understand the umbrella definition described at dictionary.com can be applied to all religions, the word culture is derived from cult, so can be applied by definition to any distinct society or movement. However, there is a deeper sense of what constitutes a religion and a cult.
Here a reasonable definition I found here: http://www.harpercollinsreligious.com.au/books/extracts/cults.html
There are cults formed within all formal religions. Although, I would say someone who professes to be either a Roman Catholic, Buddhist, Hindu, Jew, or Muslim is not a cultist. These formal religions are more than that. They are part of a social structure which encapsulates more than just a set of rules ordained by a leader or a hidden group. They are part of history, culture, and society. They are not exclusive in the strict sense, ostracizing all those who do not follow and condemning them. They do not hide there purpose or defer veneration to themselves as apposed to God. There aim is not to change your personality.
I've included a quote from the reference above, however, I would recommend reading the wikipedia definition and difficulty of defining what is a religion and a cult. It's quite long, but in my opinion, one of the best.
http://en.wikipedia.org/wiki/Cult#Problems_surrounding_the_definitions_of_a_cult
There are other differences between cults and religions. Religious groups support the family structure and can be credited with attempting to emphasise its importance in the face of the collapse of the nuclear family. They encourage family contact as well as the use of counselling services to heal relationships. Religious leaders do not assume the role of parents.
Religious orders will not disguise information about the true nature of the organisation, its beliefs and its structure. There are opportunities to question and to inquire. In the mainstream churches, the mission statements, the methods of appointments and the financial records are available to the public. All of these issues are an ?open book?. Cults, on the other hand, make a deliberate effort to conceal the true nature of the group by operating under a variety of names or withholding information from the potential recruit.
The restriction on inquiry or criticism of the organisation is a very disturbing feature of many cults. In his book, When God Becomes a Drug: Breaking the Chains of Religious Addiction and Abuse, L. Booth suggests that the discouragement of independent thinking is the primary identifying mark of a dysfunctional system. ?If you cannot question or examine what you are taught, if you cannot doubt or challenge authority, you are in danger of being victimised or abused.?
steve
