1. an extensive group of islands: "the Indonesian archipelago"
▪ a sea or stretch of water having many islands.
Word Originearly 16th century: from Italian arcipelago, from Greek arkhi- ‘chief’ + pelagos ‘sea’. The word was originally used as a proper name (the Archipelago ‘the Aegean Sea’): the general sense arose because the Aegean Sea is notable for its large numbers of islands.