Sociologists divide religious organizations into four basic types: churches, denominations, sects, and cults. The types fall along a continuum. Churches are the largest type of group and have the most influence over society. Cults are the smallest. Cults may have a great deal of influence over their members but little influence over society at large.
In sociology, a church is an established religious organization that is well integrated into the larger society. Churches have well-established rules and expect their leaders to be formally trained, educated, and ordained. They are highly organized, with a formal bureaucratic structure. One type of church is an ecclesia, a large, formally organized religious institution that is part of the state. An ecclesia provides a national religion. Most members of the nation belong to the ecclesia, and most of the members are born into the ecclesia rather than making a decision to join it. An ecclesia is closely interwoven with the state and society, exerting strong influence over both. Examples include the Roman Catholic Church in Spain, Islam in Saudi Arabia, and the Anglican Communion in England. In some ecclesiastic societies, such as Saudi Arabia, religious leaders have a great deal of influence in the government. In others, such as England, religious leaders have relatively little influence.
A denomination is a subgroup or branch of a religion that has its own tradition, interpretation of religious faith, and identity. Denominations tend to coexist on relatively positive terms with other denominations and have established their role in society. Most mainstream Protestant Christian groups, such as Baptists, Lutherans, and Methodists, are denominations. The three major branches of Judaism—Orthodox, Conservative, and Reform—can be described as denominations.
A sect is a subgroup that breaks away from a larger religious organization. A sect is sometimes an offshoot of the larger church or of a smaller denomination. Sometimes the sect breaks away in protest. Sect members may disagree with the way the larger group interprets the religion's doctrine. They may, for example, believe they should adhere to a stricter, more fundamental interpretation. Sects differ from denominations in that they are usually small, relatively new groups not as assimilated into society.
Over time, some sects dwindle away. Others develop into denominations. Most Protestant Christian denominations began as sects. For example, Anglicans broke away as a sect from the larger Roman Catholic Church. Methodists broke away as a sect from the Anglican Communion. Anglicans and Methodists are now consideration denominations. A third group of sects do not become denominations and instead become what sociologists call established or institutionalized sects. One example is the Amish Mennonites, a 300-year-old Protestant sect that continues to reject wider society.
A cult is a religious group composed of individuals who reject what they see as the values of the outside society. Like sects, cults are new, relatively small groups. Unlike sects, they often form independently rather than as an offshoot of a larger religious group. Cults usually embrace new beliefs that are outside societal norms. Cults tend to be secretive, insular, and organized around a charismatic leader. The term cult is often pejorative. However, sociologists point out that most world religions, including Christianity and Islam, began thousands of years ago as cults.