Afen

According to the Old English Dictionary:

Afn, e;

Afen

f: Afene, an; f. I. AVON, the name of a river in Somersetshire :-- East óþ Afene múþan east at the Avon's mouth. Chr. 918; Th. 190, 4. II. also of other rivers in different parts of England :-- Into Afenan múþan into Avon's mouth, Chr. 1067; Th. 342, 5. afen