A cultural system of behaviors, practices and ethics based on belief in a supernatural power. Often includes a sacred history, narratives and mythologies, oral traditions, sacred texts and symbols, and holy places that try to explain the origin of life, the universe and other phenomena.

The word religion is today used to describe a diverse taxon of social practices whose paradigmatic examples include Judaism, Christianity, Islam, Buddhism, Hinduism, Confucianism and Taoism. The etymology of the word religion hints at its use in ancient cultures to refer to a sense of devotedness or scrupulousness. As such, in western antiquity and probably in many or most other cultures, it was used to distinguish people who shared commitments based on taboos, promises, curses and oaths from those who did not.

Most scholars adopt a monothetic approach to the concept religion, treating it as a sortable category in terms of its defining properties. Such an approach can be misleading, however, because some instances share only a few of the properties that qualify them as members of the religion class.

Emile Durkheim and Paul Tillich have proposed functional definitions of religion, focusing on the role that religion plays in creating solidarity. More recently, studies have shown that those who engage in regular religious rituals tend to score higher on measures of happiness, health and civic participation. Such findings have led some scholars to conclude that a more polythetic approach to the concept religion is appropriate, one that treats it as a family resemblance concept rather than as an object of study.