An archipelago is a cluster or chain of islands in a sea, ocean, river, or lake

. The word "archipelago" comes from the Italian word "archipelago," which was used as a proper name for the Aegean Sea

. The Italian term comes from the Greek words arkhi , meaning chief, and pelagus , meaning gulf, pool, or pond

. Archipelagos can form in several ways:

• Oceanic Islands Oceanic islands are created from underwater volcanoes. The Hawaiian Islands and Galapagos Islands are examples of this type of archipelago

• Continental Fragments Continental fragments are islands that were once part of a continent and separated because of natural events

. The Farallon Islands off the coast of California are considered continental fragments

• Continental Islands These islands were once part of a continent, residing on the continental shelf, the submerged edge of a continent. The islands of the Inside Passage off the coast of British Columbia and the Canadian Arctic Archipelago are examples

• Artificial Archipelagos These are man-made island chains, such as the Palm Islands and the World Islands in Dubai, constructed for tourism or conservation, like the Marker Wadden in the Netherlands