What does Diya mean?
From the Hindi दीया (diyā), 'an oil lamp', descended from the Sanskrit dīpa ('lamp, light'). A genuine, everyday Hindi word evoking the lamps of Diwali.
What does Riya mean?
Commonly given as Sanskrit-derived riya (रिया), 'singer' or 'graceful'. It is not well attested in classical Sanskrit literature, so this meaning is popular rather than firmly documented.