What does Yash mean?
From Sanskrit yashas (यशस्), 'fame, glory, renown, success'. A widely used quality-name meaning 'glory'.
What does Ishan mean?
From the Sanskrit ईशान (īśāna), 'ruler, master'. It is an epithet of the god Shiva, also denotes the sun and the north-eastern quarter (one of the dikpalas). A genuine, well-attested Vedic/classical term.