There are numerous definitions of religion and only a few are stated here. The typical dictionary definition of religion refers to a "belief in, or the worship of, a god or gods"[23] or the "service and worship of God or the supernatural".[24] However, writers and scholars have expanded upon the "belief in god" definitions as insufficient to capture the diversity of religious thought and experience.

Peter Mandaville and Paul James define religion as "a relatively-bounded system of beliefs, symbols and practices that addresses the nature of existence, and in which communion with others and Otherness is lived as if it both takes in and spiritually transcends socially-grounded ontologies of time, space, embodiment and knowing".[25] This definition is intended, they write, to get away from the modernist dualisms or dichotomous understandings of immanence/transcendence, spirituality/materialism, and sacredness/secularity.

Edward Burnett Tylor defined religion as "the belief in spiritual beings".[26] He argued, back in 1871, that narrowing the definition to mean the belief in a supreme deity or judgment after death or idolatry and so on, would exclude many peoples from the category of religious, and thus "has the fault of identifying religion rather with particular developments than with the deeper motive which underlies them". He also argued that the belief in spiritual beings exists in all known societies.

The anthropologist Clifford Geertz defined religion as a "system of symbols which acts to establish powerful, pervasive, and long-lasting moods and motivations in men by formulating conceptions of a general order of existence and clothing these conceptions with such an aura of factuality that the moods and motivations seem uniquely realistic."[27] Alluding perhaps to Tylor's "deeper motive", Geertz remarked that "we have very little idea of how, in empirical terms, this particular miracle is accomplished. We just know that it is done, annually, weekly, daily, for some people almost hourly; and we have an enormous ethnographic literature to demonstrate it".[28] The theologian Antoine Vergote also emphasized the "cultural reality" of religion, which he defined as "the entirety of the linguistic expressions, emotions and, actions and signs that refer to a supernatural being or supernatural beings"; he took the term "supernatural" simply to mean whatever transcends the powers of nature or human agency.[29]

The sociologist Durkheim, in his seminal book The Elementary Forms of the Religious Life, defined religion as a "unified system of beliefs and practices relative to sacred things".[30] By sacred things he meant things "set apart and forbidden—beliefs and practices which unite into one single moral community called a Church, all those who adhere to them". Sacred things are not, however, limited to gods or spirits.[note 2] On the contrary, a sacred thing can be "a rock, a tree, a spring, a pebble, a piece of wood, a house, in a word, anything can be sacred".[31] Religious beliefs, myths, dogmas and legends are the representations that express the nature of these sacred things, and the virtues and powers which are attributed to them.[32]

In his book The Varieties of Religious Experience, the psychologist William James defined religion as "the feelings, acts, and experiences of individual men in their solitude, so far as they apprehend themselves to stand in relation to whatever they may consider the divine".[33] By the term "divine" James meant "any object that is godlike, whether it be a concrete deity or not"[34] to which the individual feels impelled to respond with solemnity and gravity.[35]

Echoes of James' and Durkheim's definitions are to be found in the writings of, for example, Frederick Ferré who defined religion as "one's way of valuing most comprehensively and intensively".[36] Similarly, for the theologian Paul Tillich, faith is "the state of being ultimately concerned",[37] which "is itself religion. Religion is the substance, the ground, and the depth of man's spiritual life."[38] Friedrich Schleiermacher in the late 18th century defined religion as das schlechthinnige Abhängigkeitsgefühl, commonly translated as "a feeling of absolute dependence".[39] His contemporary Hegel disagreed thoroughly, defining religion as "the Divine Spirit becoming conscious of Himself through the finite spirit."[40]

When religion is seen in terms of "sacred", "divine", intensive "valuing", or "ultimate concern", then it is possible to understand why scientific findings and philosophical criticisms (e.g. Richard Dawkins) do not necessarily disturb its adherents.[41]

An increasing number of scholars have expressed reservations about ever defining the "essence" of religion.[42] They observe that the way we use the concept today is a particularly modern construct that would not have been understood through much of history and in many cultures outside the West (or even in the West until after the Peace of Westphalia).[43]