Quick answer
Arianrhod is a girl name meaning "silver wheel".
Pronunciation: Welsh /ar.ˈjan.r̥ɔd/.
Meaning and history
Probably means "silver wheel" from Welsh arian "silver" and rhod "wheel". According to the Fourth Branch of the Mabinogi, Arianrhod was the mother of the twins Dylan and Lleu Llaw Gyffes, whom she spontaneously birthed when she stepped over a magical wand. It is speculated that in earlier myths she may have been a goddess of the moon.
Notes and context
Usage: welsh mythology