The United Nations — the big international organisation, founded in 1945 after the Second World War, where almost every country in the world sends representatives to talk instead of fight. It works on peace between countries, but also on food, health, refugees, children's rights, and the climate, through smaller bodies inside it like UNICEF, the WHO, and UNESCO. Its main office is in New York. In English it almost always takes 'the': the U.N., a U.N. report, U.N. peacekeepers (soldiers in blue helmets sent to keep two sides apart). You will see it written both with and without full stops — 'U.N.' is the older American newspaper style, 'UN' is now more common, especially in British writing. People say the two letters separately, 'you-en', never as a word. Note that in ordinary talk 'the U.N.' often means the officials and the decisions, not the building: 'The U.N. condemned the attack' means the member countries acting together.