Ethelwyn is a form of Æðelwine, a masculine Anglo-Saxon saints' name that was revived in the 19th century, but for girls. An old example of gender-bending names, the switch likely occurred due to its obvious similarities to Ethel, which ultimately shares the same Old English root, æðele meaning "noble". 
 
Clunky with a touchy of whimsy, Ethelwyn has been notably borne by Canadian poet Ethelwyn Wetherald, British artist and sculptor Ethelwyn Baker, and Ethelwyn Murray, daughter of lexicographer, James A. Murray.
 
Ethelwyn's similarity to Elowyn, Esther, and Gwendolyn might make it appealing to modern parents looking for something unexpected.

Ethelwyn

Ethelwyn Origin and Meaning