Religion is an anthropological term for any system of beliefs and practices that people hold as central to their identities. It is a very large category, covering many different kinds of ideas and practices. The field of study that studies religion is relatively new, emerging with the recognition of the powerful and pervasive role that religions have played throughout history. The anthropological concept of religion is not necessarily a clear-cut taxonomy, and it is possible for scholars to have widely divergent views about what defines a religion. However, there are two signposts that anthropologists use to sort through the many ways of thinking about religion.

One of these is the notion that a religion has to believe in an unusual kind of reality. This idea is most closely associated with the work of Emile Durkheim, who defined religion as whatever practices unite a group of people into a moral community. Those who embrace this view tend to look for religions that include beliefs in gods, spirits, or some kind of afterlife.

A second way of understanding the nature of religion is to consider its functions. This approach was developed by Clifford Geertz, who described a religion as whatever sets powerful moods and motivations in human beings by formulating conceptions of the general order of existence and clothing those concepts with such an aura of factuality that they seem uniquely realistic. While some scholars argue that this functional definition is too narrow, others are skeptical of the idea that a religion can function without its belief component.