a word with many religious meanings (and some secular as well) which should be used with great care to avoid misunderstanding:
1 - Traditional theological usage: a style of worship and its associated rituals.
2 - Sociological usage: a small religious group that exists in a state of tension with the predominant religion; e.g. Christianity in Pakistan.
3 - General religious usage: a small, recently created religious group; not a variant of an established religion. Often headed by a single charismatic leader.
4 - Evangelical usage: a religious group that does not accept Jesus as lord and savior and/or does not accept the concept of the Trinity .
5 - Popular, media usage: a small, evil religious group, often with a single charismatic leader, who engage in brainwashing and other mind control techniques -- a dangerous group to belong to.