Oceania is a continental region between Asia and the Americas. The Australian mainland is the biggest landmass with an additional 10,000 or more islands to its east. Oceania's border is defined more so by surrounding ocean and seas rather than Australia, the single dominating landmass. It is also the smallest continental region in land area and the second smallest in population after the Antarctica. Oceania is composed of four regions: Australasia, Polynesia, Melanesia, and Micronesia.
Australasia includes Australia and New Zealand and is by far the biggest region. To put this in perspective, New Zealand is bigger than all the other South Pacific Islands combined and New Zealand fits into Australia nearly 30 times.
Polynesia or the Polynesian Triangle consists of New Zealand which is the south-western anchor with Hawaii as the northern point and Easter Island to the east. Although New Zealand is part of Australasia, it is also culturally and linguistically Polynesia. Other countries here include: French Polynesia, Cook Islands, Samoa, Tonga, and Tuvalu.
Melanesia lies west of Polynesia and includes New Caledonia, Solomon Islands, New Guinea, Vanuatu, and Fiji. This region is culturally and racially distinct from Polynesia. Melanesians originate from New Guinea.
Micronesia to the north is also distinct. Island nations here includes Kiribati, Guam, Marshall Islands, Federated States of Micronesia, Northern Mariana Islands, Palau, Nauru, and Wake Island.