USN is not the abbreviation of country. USN, the abbreviation of US Navy, is a branch of the armed forces of the United States of America, which is responsible for all naval affairs. Its duty is to "equip, train and arm a naval combat force capable of winning wars, preventing invasions and ensuring freedom of sea areas."

US is the abbreviation of America, the English abbreviation of America, which originated from Uncle Sam. There are rumors in this. The abbreviation of the United States is USA, and the full name is the United States of America. The United States of America for short is a federal constitutional country, which consists of Washington, D.C., 50 states, the Commonwealth of Puerto Rico, Guam and many other overseas territories. Its main part is located in central North America. The original versions of CIA world surveys 1989 to 1996 listed the total area of the United States as 93726 10 square kilometers? 1997 was revised to 9.63 million square kilometers (plus the Great Lakes and coastal waters such as estuaries, harbors and inland seas in the United States), with a population of 3 1 10,000. It is an immigrant country with a common English.