What does Evan mean?
An anglicisation of the Welsh Iefan/Ifan, a form of John, ultimately from Hebrew 'Yochanan' meaning 'God is gracious.' A John-root grace name.
What does Dylan mean?
From Welsh, traditionally interpreted as containing an element meaning 'sea' or 'tide'; in medieval Welsh myth Dylan ail Don is a sea figure who takes to the waves at birth. The exact derivation of the first element is debated, but the sea association is ancient.