Evelyn is a matronymic English surname derived from the medieval girl's name Aveline (which is of Norman origin and represents a diminutive form of Ava). Since the 17th century, it has also been used as a given name. The earliest recorded bearer was Evelyn Pierrepoint (d. 1726), who was a grandson of the Roundhead politician Sir John Evelyn. It is still occasionally used as a boy's name, but is now more often given to girls. In some cases, the given name may represent an anglicized form of the Irish names Aibhilín and Éibhleann.
https://en.wikipedia.org/wiki/Evelyn_(name)