word | | Country name |
| Xa | Vietnam | conventional long form: Socialist Republic of Vietnam conventional short form: Vietnam local long form: Cong Hoa Xa Hoi Chu Nghia Viet Nam local short form: Viet Nam abbreviation: SRV |
| Xianggang | Hong Kong | conventional long form: Hong Kong Special Administrative Region conventional short form: Hong Kong local long form: Xianggang Tebie Xingzhengqu local short form: Xianggang abbreviation: HK |
| Xingzhengqu | Hong Kong | conventional long form: Hong Kong Special Administrative Region conventional short form: Hong Kong local long form: Xianggang Tebie Xingzhengqu local short form: Xianggang abbreviation: HK |
| Xingzhengqu | Macau | conventional long form: Macau Special Administrative Region conventional short form: Macau local long form: Aomen Tebie Xingzhengqu (Chinese); Regiao Administrativa Especial de Macau (Portuguese) local short form: Aomen (Chinese); Macau (Portuguese) |
| ya | Tanzania | conventional long form: United Republic of Tanzania conventional short form: Tanzania local long form: Jamhuri ya Muungano wa Tanzania local short form: Tanzania former: United Republic of Tanganyika and Zanzibar |
| Yaman | Yemen | ... Yemen conventional short form: Yemen local long form: Al Jumhuriyah al Yamaniyah local short form: Al Yaman former: Yemen Arab Republic [Yemen (Sanaa) or North Yemen] and People's Democratic Republic of ... |
| Yamaniyah | Yemen | ... conventional long form: Republic of Yemen conventional short form: Yemen local long form: Al Jumhuriyah al Yamaniyah local short form: Al Yaman former: Yemen Arab Republic [Yemen (Sanaa) or North Yemen] and ... |
| Yap | 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 |
| ye | Afghanistan | conventional long form: Islamic Republic of Afghanistan conventional short form: Afghanistan local long form: Jomhuri-ye Eslami-ye Afghanestan local short form: Afghanestan former: Republic of Afghanistan |
| ye | Iran | conventional long form: Islamic Republic of Iran conventional short form: Iran local long form: Jomhuri-ye Eslami-ye Iran local short form: Iran former: Persia |
| Yemen | Yemen | conventional long form: Republic of Yemen conventional short form: Yemen local long form: Al Jumhuriyah al Yamaniyah local short form: Al Yaman former: Yemen Arab Republic [Yemen (Sanaa) or North Yemen] and ... |
| Yisra | Israel | conventional long form: State of Israel conventional short form: Israel local long form: Medinat Yisra'el local short form: Yisra'el |
| Yugoslav | Macedonia | ... local short form: Makedonija note: the provisional designation used by the UN, EU, and NATO is Former Yugoslav Republic of Macedonia (FYROM) former: People's Republic of Macedonia, Socialist Republic of Macedonia |
| Yul | Bhutan | conventional long form: Kingdom of Bhutan conventional short form: Bhutan local long form: Druk Gyalkhap local short form: Druk Yul |
| yun | Armenia | conventional long form: Republic of Armenia conventional short form: Armenia local long form: Hayastani Hanrapetut'yun local short form: Hayastan former: Armenian Soviet Socialist Republic; Armenian Republic |
| Zaire | Congo, Democratic Republic of the | ... Republic of the Congo conventional short form: none local long form: Republique Democratique du Congo local short form: none former: Congo Free State, Belgian Congo, Congo/Leopoldville, Congo/Kinshasa, Zaire abbreviation: DRC |
| Zambia | Zambia | conventional long form: Republic of Zambia conventional short form: Zambia former: Northern Rhodesia |
| Zanzibar | Tanzania | conventional long form: United Republic of Tanzania conventional short form: Tanzania local long form: Jamhuri ya Muungano wa Tanzania local short form: Tanzania former: United Republic of Tanganyika and Zanzibar |
| Zhongguo | China | conventional long form: People's Republic of China conventional short form: China local long form: Zhonghua Renmin Gongheguo local short form: Zhongguo abbreviation: PRC |
| Zhonghua | China | conventional long form: People's Republic of China conventional short form: China local long form: Zhonghua Renmin Gongheguo local short form: Zhongguo abbreviation: PRC |