cult noun, often attributive \ˈkəlt\
: a small religious group that is not part of a larger and more accepted religion and that has beliefs regarded by many people as extreme or dangerous
: a situation in which people admire and care about something or someone very much or too much
: a small group of very devoted supporters or fans
I would think that anytime people are not free to have their own opinion, are being micromanaged in their life, or are not free to leave the group without harassment of retribution, you might be in a cult.
If you ask yourself the question "Am I in a cult?" you are probably in a cult.