Religion is a broad category of human beliefs and practices that people believe to be important. It can be a source of strength and unity for communities, but it can also be a source of division and stress, particularly when people with different religious beliefs are not treated equally in society.
The word religion is derived from the Latin religio, which means “scrupulousness” or “devotedness.” In early antiquity, it is likely that in many cultures the concept of religion was used to refer to all systems of belief. It is also possible that the concept was subsequently used to refer to certain aspects of culture, especially those that generated social cohesion or provided orientation in life, such as the Sacred, God, or other deities.
Today, the concept of religion is most commonly employed to refer to a set of practices and beliefs that are common to a group of people or to a cultural region. The best known religions are Christianity, Islam, Judaism, and Hinduism, although a number of others have millions or billions of followers. Of these, Islam is the fastest growing and, according to the latest estimates, now has over 1.9 billion adherents worldwide.
While many scholars use functional criteria to define religion, some of them prefer a more structural approach that considers the defining properties of a given type of phenomenon. For example, Edward Tylor argues that the minimum criterion for the existence of religion is belief in spiritual beings. Similarly, Paul Tillich argues that the essence of religion is ultimate concern. These are exemplary of single-criterion monothetic definitions.