Papua New Guinea UK /ˈpæp.uː.ə ˌnjuː ˈɡɪn.i/US /ˈpæp.u.ə ˌnu ˈɡɪn.i/ noun1 •A country in Oceania. Official name: Independent State of Papua New Guinea. Capital and largest city: Port Moresby.The Prime Minister of Papua New Guinea has declared a nine-month state of emergency in the country’s rugged Southern Highlands province in response to several days of riots. — 2018