ar·chi·pel·a·go 
(är′kə-pĕlə-gō′, är′chə-)
(är′kə-pĕlə-gō′, är′chə-)n. pl. ar·chi·pel·a·goes or ar·chi·pel·a·gos
1. A large group of islands: the Philippine archipelago.
2. A sea, such as the Aegean, containing a large number of scattered islands.
[Italian Arcipelago, the Aegean Sea, alteration (influenced by arci-, chief, archi-) of Medieval Latin Ēgēopelagus : Latin Aegaeus, Ēgēus, Aegean (from Greek Aigaios) + Latin pelagus, sea (from Greek pelagos; see plāk-1 in the Appendix of Indo-European roots).]
ar′chi·pe·lagic (-pə-lăjĭk) adj.