An archipelago is a landform which consists of a chain or cluster of islands. Archipelagoes usually occur in the open sea; less commonly a large land mass may neighbour them. Archipelagos are often volcanic, forming along ocean ridges or hot spots, but there are many other processes involved in their construction, including erosion and deposition.
The word comes from the Aegean Sea (ItalianArcipelago), which literally means "chief sea", from Greekarkhi (leader) and pelagos (sea).
