In The Witcher 2, the island is named the Isle of Avallach. During one of Geralt's flashbacks, the player is told about the time that the witcher and Yennefer spent there, before she was taken by the Wild Hunt.
In The Witcher 3, the island is referred to as the Isle of Avalon during conversations between Ciri and Geralt after she is found.
The name of the island in Polish is "Wyspa Jabłoni". "Jabłoni" is the equivalent of the apple genus Malus. In Arthurian legends, the island of Avalon (derived from the Welsh phrase "Ynys Afallach" , meaning roughly "Orchard Island", and the orchard typically understood to be one of apples) was known for its beautiful apples and the Lady of the Lake is often associated with the scent of apples. This particular theme is revisited many times in Sapkowski's works.