Avalon --probably from the Welsh word afal, meaning apple-- is a legendary island featured in the Arthurian legend, famous for its beautiful apples. It is the place where King Arthur's sword Caliburn (Excalibur) was forged and later where Arthur is taken to recover from his wounds after the Battle of Camlann.
As an "Isle of the Blessed" Avalon has parallels elsewhere in Indo-European mythology, in particular the Irish Tír na nÓg and the Greek Hesperides, also noted for its apples. Avalon was associated from an early date with immortal beings such as Morgan le Fay.
Geoffrey of Monmouth called it in Latin Insula Avallonis in the Historia. In the later Vita Merlini he called it Insula Pomorum the "isle of apples". The name is generally considered to be of Welsh origin, derived from Old Welsh abal "apple" or aball "apple tree".
(http://www.freewebs.com/the_isle_of_avalon_rpg/38506999MyeIEU_ph.jpg)