The name used by Geoffrey in his Vita Merlini to refer to Avalon, the paradisiacal land of the dead.
The use of this name possibly derives from the Irish Emhain Abhlach, an island that is associated with the Irish god of the sea Manannán Mac Lir and whose name means “Emhain of the Apple Trees.” Irish tradition makes this island the Isle of Arran.
Source
Vita Merlini | Geoffrey of Monmouth, c. 1150