What does Carys mean?
A modern Welsh name formed from the stem of the verb caru 'to love' (compare car 'beloved friend', cariad 'love'). A genuine Welsh 'love' root; the variant Cerys is read the same way.
What does Rhiannon mean?
Thought to derive from the reconstructed Celtic 'Rigantona', meaning 'great queen' (from the root 'rigani', queen). A figure of sovereignty in the Welsh Mabinogi. The reconstruction is scholarly, so the 'great queen' sense is widely accepted but not attested directly.