open sea(part of the sea) noun [UK: ˈəʊ.pən siː] [US: ˈoʊ.pən ˈsiː]
archipiélagonoun {m}
archipelago [archipelagos](group of islands) noun [UK: ˌɑːk.ɪ.ˈpe.lə.ɡəʊ] [US: ˌɑːrk.ə.ˈpe.ləˌɡo.ʊ]The Falkland Islands are an archipelago. = Las Islas Malvinas son un archipiélago.