What does Reyansh mean?
A modern coinage usually read as 'ray of light', often analysed as 'ray' plus the Sanskrit amsha (अंश, 'portion/part'), giving a devotional reading 'a part of Vishnu'. The Vishnu link is an interpretation built on amsha rather than a documented classical meaning.
What does Aditya mean?
From Sanskrit Aditya (आदित्य), 'belonging to Aditi', a name of the sun god Surya and collectively of the solar deities born of the goddess Aditi. A well-attested classical name meaning 'the sun'.