▶ USAGE The abbreviation for United Nations Organization is UNO
United Nations in British English
noun(functioning as singular or plural)
1.
an international organization of independent states, with its headquarters in New York City, that was formed in 1945 to promote peace and international cooperation and security
Abbreviation: UN
2.
(in World War II) a coalition of 26 nations that signed a joint declaration in Jan 1942, pledging their full resources to defeating the Axis powers