Rhiannon is a female given name of Welsh origin. It is derived from the Welsh word "riain," meaning "queen," and "annon," meaning "great" or "splendid." The name Rhiannon therefore means "great queen" or "splendid queen." In Celtic mythology, Rhiannon is an Otherworldly goddess associated with beauty, horses, fertility, and sovereignty. She is often depicted as a woman riding a white horse and is sometimes associated with the Irish goddess of the same name. The name Rhiannon became popular in English-speaking countries in the 19th century due to its romanticized association with Celtic mythology and literature.