Oceania, also known as Oceanica, is a region centred on the islands of the tropical Pacific Ocean. Opinions of what constitutes Oceania range from its three subregions of Melanesia, Micronesia, and Polynesia
to, more broadly, the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago.
or biogeographically as a synonym for either the Australasian ecozone (Wallacea and Australasia) or the Pacific ecozone (Melanesia, Polynesia, and Micronesia apart either from New Zealand or from mainland New Guinea).