The word “ritual” is used in three different, though related, ways. First, ritual is conceived as a kind of action. Second, ritual is a cultural domain, arena, stage, or field, in and out of which people act and are acted upon. Third, ritual is sometimes conceived as an actor in its own right. ‘Definitions, types, domains’ explains the limitations of definitions and assesses the wide-ranging scholarship on what ritual is. There are three concepts that can be distinguished from one another, though their usage tends to overlap: ritualization, rites, and ritual. The differences between religious ritual (liturgy) and political ritual and civil religion, often referred to as ceremony, are also discussed.