Oceania vs. Australia

Oceania

[oh-shee-an-ee-uh, -ah-nee-uh] / ˌoʊ ʃiˈæn i ə, -ˈɑ ni ə /

Also Oceanica

noun

the islands of the central and southern Pacific, including Micronesia, Melanesia, Polynesia, and traditionally Australasia. About 3,450,000 sq. mi. (8,935,500 sq. km).

Australia

[aw-streyl-yuh] / ɔˈstreɪl yə /

a continent southeast of Asia, between the Indian and Pacific Oceans. 2,948,366 square miles (7,636,270 square kilometers).
Commonwealth of Australia, a member of the Commonwealth of Nations, consisting of the federated states and territories of Australia and Tasmania. 2,974,581 square miles (7,704,165 square kilometers). Canberra.