an independent republic in the W Pacific Ocean, comprising the E part of New Guinea and numerous near-lying islands, including the Bismarck Archipelago, the Admiralty Islands, the Trobriand Islands, and Bougainville and Buka in the Solomon Islands: a former Australian Trusteeship Territory; independent since 1975; member of the Commonwealth of Nations. 178,260 sq. mi. (461,693 sq. km).
Capital: Port Moresby.