Christendom: Traditionally, the part of the world traditionally dominated by Christianity: most of Europe, Australasia and the Americas, plus parts of the Third World. This ignores the social importance of migrant communities from non-Christian societies of the Third World.

Churches: Established, ie respectable, religious organizations claiming a monopoly of truth and sometimes enjoying a monopoly position in a society. According to RCT, characterized by low religious vitality and efficiency.

Compensators: In RCT, postulations of reward according to explanations that are not readily susceptible to unambiguous evaluation: roughly translated, promises of Rewards of some generality.

Costs. In RCT, whatever humans attempt to avoid.

Cults: Deviant organizations which feature religious innovation (RCT) or do not claim a monopoly of religious truth (Wallis/Bruce). Scientology can be regarded as a cult in as much as it is innovative, and is so in RCT, but Bruce classes it as Sectarian rather than Cultic because it does claim a monopoly of religious truth.

Denominations: Established, ie respectable, religious organizations which do not claim a monopoly of truth. According to RCT, characterized by low religious vitality and efficiency.

Deviance: In RCT this refers to new religious organizations in tension with the prevailing religious establishment, eg Sects or Cults.

Eschatological: Refers to death and last judgement.

Exchange ratio: In RCT, the balance of Rewards and Costs in an exchange.

Exchange theory: Homans's famous paper, "Social Behavior as Exchange" led sociologists to refer to his work as exchange theory (though Homans preferred instead "social behaviorism"). Homans's interest is the individual who enters exchange relationships, in which social rewards and costs determine individual choices.

Explanations: In RCT, statements about how and why rewards may be obtained and cost are incurred.

Freeriders: Those who do not contribute in the provision of a public good, but enjoy these goods anyway. Since providing a public goods costs time and/or money, and since you can never be certain that the good will ultimately be provided (that the collective action will succeed), freeriding is the rational strategy. RCT is concerned with how Sects manage to avoid the problem of freeriders by maintaining standards of strictness.

Gods: In RCT, supernatural beings having the attributes of consciousness and desire.

High tension: See Tension.

Intrabrand competition: In RCT, competition within a religious "firm" like the Catholic Church or Islam, as opposed to the more established concept of competition between firms, which is known as Interbrand competition.

Low tension: See Tension.

Magic: In RCT, specific compensators that promise to provide desired rewards without regard for evidence concerning the designated means.

Market: In Economics, the existence of a choice of suppliers. RCT postulates that there are religious markets so long as there is not a religious monopoly, and that the more diverse the market is, the better for religious vitality.

Monopoly: In Economics, the situation in which one producer is the sole provider of goods and can therefore choose what price to charge. RCT extends this to the religious market and sees state based churches as religious monopolies characterized by small congregations, inefficient priests and low religious vitality generally.

Niebuhr thesis: This is that radical sects gradually and consistently evolve into comfortable denominations at ease with the world around them.

Rational choice theory: The idea that all action is fundamentally 'rational' in character and that people calculate the likely costs and benefits of any action before deciding what to do is common in Economics. This approach to theory is known as rational choice theory, and its application to social interaction takes the form of exchange theory. In RCT, as a theory of religion, it means that people will seek the religious organization which best satisfies their needs.

Rationalization: In ST, the move away from supernatural to rational and empirical modes of thought.

Religion: Has many definitions - most of them involve the idea of supernatural agency.

Religiosity: Simply, the condition of being religious. No pejorative connotation is present in sociological use of this term. Effectively it is similar to religious vitality, but is normally applied to individual beliefs rather than to religious organizations.

Religious diversity: The number of different religious organizations available to join in a society, however this is to be measured. RCT states that this is directly correlated with religious vitality.

Religious goods: In RCT, anything that is provided by religious organizations.

Religious organizations: Churches, denominations, sects and cults.

Religious market: See Market.

Religious monopoly: See Monopoly.

Religious pluralism: Effectively, the same as religious diversity.

Religious services: Same as religious goods.

Religious specialists: In RCT, priests and magicians.

Religious vitality: The importance and popularity of religion in a society, however this is to be measured - effectively the same as "religious enthusiasm" or "religious observance" as far as the Hot Topic is concerned.

Rewards: In RCT, anything humans will incur costs to obtain.

Schisms: Splits within a Church which lead to the formation of new Sects or Cults.

Sects: In RCT, deviant organizations which, however, follow an established religion and claim a monopoly of religious truth; characterized by high tension and commitment.

Secular: Confusingly in the context of Secularization, this word can mean both nonreligious and longterm. ST states that Western society is moving towards being secular (nonreligious) as a secular (longterm) trend.

Secularism: The promotion of secular policies like the separation of church and state. Not to be confused with Secularization, which aims to be a purely objective and value-free theory of in the sociology of religion. The USA is a secular state because the Constitution forbids establishment of a religion, but it is not secularised compared with much of the rest of the Western world.

Secularization: In ST, the tendency of certain advanced societies to lose their religious commitment in the long term. In RCT, the tendency of religious organizations to lose tension and commitment and become churches or denominations, at which point new sects and cults grow up to replace them.

Social differentiation: In ST, the process by which specialised roles and institutions develop to handle specific functions previously carried out by one role or institution. For instance education, health care, welfare and social control now all have specialist institutions, whereas the religious organizations formerly looked after many of these functions and have therefore lost much of their social importance.

Societalization: In ST, the process by which life ceases to be dominated by close-knit integrated small scale communities and is increasingly dominated by larger societies like the nation state. Religion draws its strength from the community, so this process has reduced its social importance.

Startup costs: In RCT, the cost involved in starting a new religious movement. Religious monopolies mean high startup costs for new religions and are associated with high tension.

Tautologies: Statements that are necessarily true, either because they are logical or mathematical in nature, or because they are truisms and true by definition.

Teleological: Refers to purposive goal-directed behaviour or explanation. The "hard" ST prediction that religion will continue to decline in the future has been called teleological, although it arguably is not really so as there is emphatically no purpose involved in such social changes - it is just that the word connotes a longterm prediction.

Tension: In RCT, refers to new religious organizations, eg Sects or Cults, competing with the prevailing religious establishment, eg a Church and in high tension with the society. Churches and denominations are characterised by low tension.

Theocratic: Refers to societies ruled by clergy.

Third World: Roughly means the relatively "undeveloped" and predominantly poorer countries of Asia, Africa and Latin America, the First World being the richer countries of North America, Western Europe and Australasia; the Second World was the former Communist world of Eastern Europe and the USSR.

West, or Western World: Essentially the First World - see Third World.