What is "arrephoros"

An Arrephoros was a girl acolyte in the cult of Athena Polias on the Athenian Acropolis. They were seven to eleven years old. According to Pausanias, two Arrephoroi lived for a year on the Acropolis and concluded their term with a mystery rite called the Arrhephoria: they carried unknown objects into an underground cavern, and there exchanged them for other unknown objects.

The lexicon of Harpocration states (s.v. Arrêphorein) that there were four Arrephoroi and that two supervised the weaving of the Panathenaic peplos.