Rhiannon comes from the Welsh — from Rigantona, meaning "great queen" or "divine queen." In the medieval Welsh mythological cycle The Mabinogion, Rhiannon is one of the central figures: a queen of the Otherworld who appears on a magical white horse, the embodiment of grace under terrible injustice.
Fleetwood Mac's 1975 song "Rhiannon" (written by Stevie Nicks, inspired by the myth) brought the name international attention. Today it remains in continuous use in Wales and is rising in the U.S.
Rhiannon reduces to seven — the number of mythic depth.