you.N.O stands for United Nations Organization. It is basically an international concern that was established in order to facilitate cooperation in International law, security, economic development, social progress, human rights and world peace.
United Nations Organization or UN, as it is popularly called, was established in the year 1945. It replaced the League ot Nations. The first President of United Nations who is known as the Secretary General was Trygve Lie. However, from 1945-1946 Sir Gladwyn Jebb served as Acting Secretary General.