rite de passage

rite of passage (ceremony or series of ceremonies to celebrate a passage or transition from one stage of a person’s life to another; any significant event or experience that marks a transition from one stage of a person’s life to another)

From rite + de + passage, literally “rite of passage”. Coined by French ethnographer and folklorist Arnold van Gennep (1873–1957) and popularized in his work Les rites de passage (1909).