SECT

Cult

Sect is usually contrasted with churches or denominations.

Sects are thought to be small and inward-looking religious or spiritual groups which reject the values of the wider society. Examples of sects would be the Jehovah's Witnesses, Salvation Army, Christian Science.

These sects or groups typically begin with a charismatic leader who articulates a strong rejection of the compromises made with the secular world by other religions.

Over time, as sect leadership is routinized and members experience some upward mobility, there tends to be more acceptance of worldly matters and secular values.

Sects are differentiated by a number of doctrinal differences and have many beliefs and practices in common with the religion or party that they have broken off from. A denomination in contrast, is a large, well-established religious group.

From the Latin secta (from sequi to follow), meaning a course of action or way of life. Sectarianism is sometimes defined in the sociology of religion as a worldview that emphasizes the unique legitimacy of believers' creed and practices and that heightens tension with the larger society by engaging in boundary-maintaining practices. - McGuire, Meredith B. "Religion: the Social Context" fifth edition (2002) ISBN 0-534-54126-7 page 338 

Sectarius or sectilis also refer to a scission or cut, but this meaning is, in contrast to popular opinion, unrelated to the etymology of the word. A sectator is a loyal guide, adherent or follower.

Scientology: Therapeutic Cult to Religious Sect 
Roy Wallis, University of Stirling 
Prevailing conceptions of the cult are criticized. A new typology of religious collectivities is elaborated and related to a theory of the development of cults. This theory claims that a central feature of the cult is `epistemological individualism'. The central characteristic of the sect on the other hand is `epistemological authoritarianism'. The process of sectarianization therefore involves the arrogation of authority typically on the basis of a claim to a new and superior revelation. Sectarianization is portrayed as a strategy with particular appeal to the leaders of cults faced with the problems of managing and maintaining a fragile institution. These processes are illustrated from the development of Scientology. - soc.sagepub.com/cgi/content/abstract/9/1/89

The main factors that seems to produce political sects is the rigid continued adherence to a doctrine or idea after its time has passed, or after it has ceased to have clear applicability to a changing reality.