A ritual is a repetitive, organised sequence of actions or behaviours that changes the state of an individual, group, or environment, without conscious understanding, emotional context, or symbolic meaning.
What is considered a ritual may vary by culture. For instance: eating food together as part of a social ritual is a Human habit that some Klingons find hard to understand, as they consider the consumption of food merely a means of maintaining bodily functions. (TNG novel: The Captains' Honor)