as far as most English speakers ( at least English speakers in Australia and New Zealand ) are concerned it is a vague geographical area encompassing anything from Australia/New Zealand/Polynesia/Melanesia/Papua New Guinea right up to the whole Pacific Basin - I am not aware that there is an exact definition in English , it varies by context and by where you went to school , but it is certainly not just referring to the specific continental land mass that the country of Australia occupies . Although the usage varies all the uses I am aware of include a considerable area of Ocean , and a lot of islands ( such as New Zealand ) which are not part of any continental land mass