word | | Country name |
| nyu | Niue | conventional long form: none conventional short form: Niue note: pronounciation falls between nyu-way and new-way, but not like new-wee former: Savage Island |
| NZ | New Zealand | conventional long form: none conventional short form: New Zealand abbreviation: NZ |
| Ocean | British Indian Ocean Territory | conventional long form: British Indian Ocean Territory conventional short form: none abbreviation: BIOT |
| Oceania | French Polynesia | ... form: Overseas Lands of French Polynesia conventional short form: French Polynesia local long form: Pays d'outre-mer de la Polynesie Francaise local short form: Polynesie Francaise former: French Colony of Oceania |
| Oeno | Pitcairn Islands | conventional long form: Pitcairn, Henderson, Ducie, and Oeno Islands conventional short form: Pitcairn Islands |
| Oesterreich | Austria | conventional long form: Republic of Austria conventional short form: Austria local long form: Republik Oesterreich local short form: Oesterreich |
| oloto | Samoa | conventional long form: Independent State of Samoa conventional short form: Samoa local long form: Malo Sa'oloto Tuto'atasi o Samoa local short form: Samoa former: Western Samoa |
| Oman | Oman | conventional long form: Sultanate of Oman conventional short form: Oman local long form: Saltanat Uman local short form: Uman former: Muscat and Oman |
| Oman | United Arab Emirates | conventional long form: United Arab Emirates conventional short form: none local long form: Al Imarat al Arabiyah al Muttahidah local short form: none former: Trucial Oman, Trucial States abbreviation: UAE |
| Oriental | Uruguay | conventional long form: Oriental Republic of Uruguay conventional short form: Uruguay local long form: Republica Oriental del Uruguay local short form: Uruguay former: Banda Oriental, Cisplatine Province |
| Outer | Mongolia | conventional long form: none conventional short form: Mongolia local long form: none local short form: Mongol Uls former: Outer Mongolia |
| outre | French Polynesia | ... form: Overseas Lands of French Polynesia conventional short form: French Polynesia local long form: Pays d'outre-mer de la Polynesie Francaise local short form: Polynesie Francaise former: French Colony of Oceania |
| outre | Saint Barthelemy | conventional long form: Overseas Collectivity of Saint Barthelemy conventional short form: Saint Barthelemy local long form: Collectivite d'outre mer de Saint-Barthelemy local short form: Saint-Barthelemy |
| outre | Saint Martin | conventional long form: Overseas Collectivity of Saint Martin conventional short form: Saint Martin local long form: Collectivity d'outre mer de Saint-Martin local short form: Saint-Martin |
| Overseas | French Polynesia | conventional long form: Overseas Lands of French Polynesia conventional short form: French Polynesia local long form: Pays d'outre-mer de la Polynesie Francaise local short form: Polynesie Francaise former: French Colony ... |
| Overseas | Saint Barthelemy | conventional long form: Overseas Collectivity of Saint Barthelemy conventional short form: Saint Barthelemy local long form: Collectivite d'outre mer de Saint-Barthelemy local short form: Saint-Barthelemy |
| Overseas | Saint Martin | conventional long form: Overseas Collectivity of Saint Martin conventional short form: Saint Martin local long form: Collectivity d'outre mer de Saint-Martin local short form: Saint-Martin |
| Ozbekiston | Uzbekistan | conventional long form: Republic of Uzbekistan conventional short form: Uzbekistan local long form: Ozbekiston Respublikasi local short form: Ozbekiston former: Uzbek Soviet Socialist Republic |
| Pacific | Marshall Islands | ... Marshall Islands conventional short form: Marshall Islands local long form: Republic of the Marshall Islands local short form: Marshall Islands abbreviation: RMI former: Trust Territory of the Pacific Islands, Marshall Islands District |
| Pacific | Micronesia, Federated States of | ... States of Micronesia conventional short form: none local long form: Federated States of Micronesia local short form: none former: Trust Territory of the Pacific Islands, Ponape, Truk, and Yap Districts abbreviation: FSM |
| Pacific | Northern Mariana Islands | conventional long form: Commonwealth of the Northern Mariana Islands conventional short form: Northern Mariana Islands abbreviation: CNMI former: Trust Territory of the Pacific Islands, Mariana Islands District |