oxford american dictionary
archipelago
|ˌärkəˈpeləˌgō|
noun ( pl. –gos or –goes)
a group of islands.
• a sea or stretch of water containing many islands.
ORIGIN early 16th cent.: from Italian arcipelago, from Greek arkhi– ‘chief’ + pelagos ‘sea.’ The word was originally used as a proper name ( the Archipelago [the Aegean Sea] ): the generalization of meaning occurred because the Aegean Sea is remarkable for its large numbers of islands.
