ar·chi·pel·a·go (är'kə-pěl'ə-gō') n.
pl.ar·chi·pel·a·goes or ar·chi·pel·a·gos
A large group of islands: the Philippine archipelago.
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 Indo-European roots).] ar'chi·pe·lag'ic (-pə-lāj'ĭk) adj.
An electronic communications network formed in 1996 as one of the four original ECNs approved by the SEC. The network offers what is essentially a national and visible limit order book for stocks. In 2001 Archipelago received SEC approval to launch Archipelago Exchange (ArcaEx), an electronic stock market for New York Stock Exchange, American Stock Exchange, and Nasdaq securities. ArcaEx is operated as a regulated facility of the Pacific Exchange.