Oceania (sometimes Oceanica) is a geographical, and often geopolitical, region consisting of numerous lands—mostly islands in the Pacific Ocean and vicinity. The term "Oceania" was coined in 1831 by French explorer Dumont d'Urville. The term is also sometimes used to denote a continent comprising Australia and proximate Pacific islands, and is one of eight terrestrial ecozones. The boundaries of Oceania are defined in a number of ways. Most definitions include Australia, New Zealand and all or part of the Malay Archipelago. Ethnologically, the islands that are included in Oceania are divided into the subregions of Melanesia, Micronesia, and Polynesia. As with any region, however, interpretations vary; increasingly, geographers and scientists divide Oceania into Near Oceania and Remote Oceania. Most of Oceania consists of island nations comprising thousands of coral atolls and volcanic islands, with small human populations. Australia is the only continental country but Indonesia has land borders with Papua New Guinea, East Timor, and Malaysia. If the Australia-New Guinea continent is included then the highest point is Puncak Jaya in Papua at 4,884 m (16,024 ft) and the lowest point is Lake Eyre, Australia at 16 m (52 ft) below sea level.
from Wikipedia - http://en.wikipedia.org/wiki/Oceania