Oceania (ōshēăn'ēu, –ā'nēu) [key]or Oceanica (ōshēăn'iku) [key], collective name for the approximately 25,000 islands of the Pacific, usually excluding such nontropical areas as the Ryukyu and Aleutian islands and Japan, as well as Taiwan, Indonesia, and the Philippines, whose populations are more closely related to mainland Asia. Oceania is generally considered synonomous with the South Sea Islands and is divided ethnologically into Melanesia, Micronesia, and Polynesia.
