A rite is typically a religious action performed as part of a solemn or sacred ceremony. Some rites are only performed once—baptism is a rite, for instance. The rites performed only once are sometimes called “rites of passage,” because the idea is that every person has to undertake them once.
In pre-Christian times, animal sacrifices were considered a rite. The Eleusinian Mysteries were also an initiation rite common to much of the pre-Christian Greek world.
Sometimes we use the word “rite” in non-religious ways. The first time you kill a deer, it might be a rite to smear your cheeks with its blood. But there are other, more common, secular (meaning: non-religious) rites: a graduation ceremony, a quinceañera party—even a morning coffee can be understood as a rite if attended to with care. Don’t forget weddings, too!