What does Aarush mean?
From Sanskrit arusha (आरुष), 'reddish, red of dawn', commonly glossed as 'the first ray of the sun'. The 'red/dawn' sense is the attested one; 'first ray of sun' is the popular reading.
What does Pranav mean?
From Sanskrit pranava (प्रणव), the term for the sacred syllable 'Om', regarded as the primordial sound. A spiritually weighted name meaning the mystic syllable itself.