His name is two Anglo Saxon words, æðel (prince) and wine (friend protector).
He takes his suffix from Athelney, the island where he lived. Athelney was made famous as the island fort in the Somerset marshes from where Alfred the Great launched his conquest of the Danes, two centuries after Æthelwine lived there. The Anglo-Saxon name of Athelney isle was "Æðelinga íeg", thought to mean the "Island of Princes" (æðeling) and as it had this name prior to Alfred it is possible that it derived from Æthelwine, or that it was an established royal residence, fort or refuge of some type. To give thanks for his victory, Alfred founded on the Isle in 888 AD, a monastery, Athelney Abbey.[8]