Answer
The word sect comes from the Latin word secta, which means “school of thought.” It is a subjective term that may apply to a religious faith or denomination, or it may refer to a heretical splinter group. Sometimes, the connotation is one of disapproval, similar to the “destructive heresies” spoken of in 2 Peter 2:1, though there are no consistent or accepted exemplars to use to identify a sect.
Sects are found in all religions. Islam has Sunnis and Shias, Judaism has Orthodox and Karaites, Hinduism has Shiyaism and Shaktism, and Christianity has Baptists and Lutherans. These are all examples of religious sects, and they can be thought of as “branches” of different religions. There are also non-religious sects, such as capitalists and socialists among economists, or Freudians and Jungians among psychiatrists.
In contradistinction, the word cult always carries a negative connotation. There are specific criteria used to identify a cult. In Combatting Cult Mind Control, deprogrammer Steven Hassan singles out what he refers to as “destructive cults,” which he defines as “a pyramid-shaped authoritarian regime with a person or group of people that have dictatorial control. It uses deception in recruiting new members (e.g. people are NOT told up front what the group is, what the group actually believes and what will be expected of them if they become members).” Hassan also correctly points out that cults are not only religious; they may also be commercial or secular in nature.
Hassan developed the BITE acronym, which describes the components employed by destructive cults using mind control. BITE covers the following areas of control:
Behavior Control: An individual’s associations, living arrangements, food, clothing, sleeping habits, finances, etc., are strictly controlled.
Information Control: Cult leaders deliberately withhold or distort information, lie, propagandize, and limit access to other sources of information.
Thought Control: Cult leaders use loaded words and language, discourage critical thinking, bar any speech critical of cult leaders or policies, and teach an “us vs. them” doctrine.
Emotional Control: Leaders manipulate their followers via fear (including the fear of losing salvation, fear of shunning, etc.), guilt, and indoctrination.
From a Christian perspective, a cult is any group that follows teachings that contradict orthodox Christian doctrine and promote heresy. Under this definition, the Watchtower Society and the Latter-day Saints (Mormons) are both cults.
Because not all cults are immediately recognized as such, and some people may easily confuse cults with sects or denominations, it is critical to follow the example of the Bereans in Acts 17:11: "Now the Bereans . . . received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true." Always research the beliefs of a group before committing to it, examine its behaviors and doctrines in light of the Bible, and beware of the methods listed in the BITE model. Talk to members, but refuse to be coerced by them. Importantly, if something doesn’t seem right, don’t do it.