Every dictionary has a definition of religion, but not every definition is equally good. Some are decent, but others are horrible. Sometimes older dictionaries have better definitions than newer ones, but more recent comprehensive dictionaries tend to have the better overall definitions of all. It's easier to understand what religion is if you understand the advantages and disadvantages of some of the more commonly cited definitions found in dictionaries.
Websters Revised Unabridged Dictionary, 1913:
- Religion: The outward act or form by which men indicate their recognition of the existence of a god or of gods having power over their destiny, to whom obedience, service, and honor are due; the feeling or expression of human love, fear, or awe of some superhuman and overruling power, whether by profession of belief, by observance of rites and ceremonies, or by the conduct of life; a system of faith and worship; a manifestation of piety.
This definition, like many of the older ones cited here, focuses on belief in the existence of deities. More than that, it specifies deities which have power over our lives and to whom we owe some level of obedience and service. This excludes from religion many forms of Buddhism, religious humanism, and even deistic belief systems. Because of that, this definition is too narrow and exclusive to be very useful but it is the sort of definition you will find many people using.
On the positive side, though, this definition acknowledges the important role played by rites and ceremonies in religious belief. Many definitions of religion fail to point them out as being relevant.
The New Century Dictionary, 1927:
- Religion: Recognition on the part of man of a controlling superhuman power entitled to obedience, reverence and worship; the feeling or the spiritual attitude of those recognizing such a controlling power; also, a manifestation of such feeling in conduct or life; the practice of sacred rites or observances.
The Readers Digest Great Encyclopedic Dictionary, 1966:
- Religion:
1. The beliefs, attitudes, emotions, behavior, etc., constituting mans relationship with the powers and principles of the universe, especially with a deity or deities; also, any particular system of such beliefs, attitudes, etc.
2. An essential part or a practical test of the spiritual life.
3. An object of conscientious devotion or scrupulous care: e.g. His work is a religion to him.
This definition is noteworthy for making explicit the fact that belief in gods and, in particular, gods which control our destiny is not necessary for religion. Although it acknowledges that belief in a god or gods is common, it is clear that religion has to do with wider issues regarding the nature of the universe and reality.
This definition also points out how religion encompasses different aspects of human existence, including attitudes and behavior. It fails to note the important social aspects of religious system, though.

