1. a set of beliefs concerning the cause, nature, and purpose of the universe, especially when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs.
2. a specific fundamental set of beliefs and practices generally agreed upon by a number of persons or sects: the Christian religion; the Buddhist religion.
3. the body of persons adhering to a particular set of beliefs and practices: a world council of religions.
4. the life or state of a monk, nun, etc.: to enter religion.
5. the practice of religious beliefs; ritual observance of faith.