An archipelago (i/ɑrkɨˈpɛləɡoʊ/ ark-i-PEL-ə-goh), sometimes called an island group or island chain, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- ("chief") and πέλαγος – pélagos ("sea") through the Italian arcipelago. In Italian, possibly following a tradition of antiquity, the Arcipelago (from medieval Greek *ἀρχιπέλαγος) was the proper name for the Aegean Sea and, later, usage shifted to refer to the Aegean Islands (since the sea is remarkable for its large number of islands). It is now used to refer to any island group or, sometimes, to a sea containing a large number of scattered islands such as the Aegean Sea.
Read more about Archipelago: Types of Archipelago