Airan Island or "airantou" is the name given to this unknown island 130 years ago by the current inhabitants. It's surrounded by dangerous whirlpools that prevent escape.
Airan Island is the main location for all the events that occur during the manga/anime series Nagasarete Airantou.
The name of the island was selected to name after the ship that the survivors traveled on before it sunk. The name of the ship was called "The Island". Using the Japanese katakana, the English word for 'Island' would be pronounced as "Airanto". The Kanji added to the name of an island(島) can be pronounced as "tou". They simply removed the "to" from the pronunciation of the word 'island' and replaced it with the "tou" from the Japanese word for island.
Technically, the word "airan-tou" could mean Blue Orchard Island, but the ship they were traveling on was not called "Blue Orchard".