A ritual "is a sequence of activities involving gestures, words, and objects, performed in a sequestered place, and performed according to set sequence." Rituals may be prescribed by the traditions of a community, including a religious community. Rituals are characterized by formalism, traditionalism, invariance, rule-governance, sacral symbolism and performance.
Rituals of various kinds are a feature of almost all known human societies, past or present. They include not only the various worship rites and sacraments of organized religions and cults, but also the rites of passage of certain societies, atonement and purification rites, oaths of allegiance, dedication ceremonies, coronations and presidential inaugurations, marriages and funerals, school "rush" traditions and graduations, club meetings, sports events, Halloween parties, veterans parades, Christmas shopping and more. Many activities that are ostensibly performed for concrete purposes, such as jury trials, execution of criminals, and scientific symposia, are loaded with purely symbolic actions prescribed by regulations or tradition, and thus partly ritualistic in nature. Even common actions like hand-shaking and saying hello may be termed rituals.
The field of ritual studies has seen a number of conflicting definitions of the term. One given by Kyriakidis is that a ritual is an outsider's or "etic" category for a set activity (or set of actions) that, to the outsider, seems irrational, non-contiguous, or illogical. The term can be used also by the insider or "emic" performer as an acknowledgement that this activity can be seen as such by the uninitiated onlooker.
In psychology, the term ritual is sometimes used in a technical sense for a repetitive behavior systematically used by a person to neutralize or prevent anxiety; it is a symptom of obsessive–compulsive disorder.