DISCLAIMER: VERY LONG (BORING FOR SOME) AND DETAILED ANSWER: By now, you must have got from the other answers that USA i.e. United States of America is part of North America. The reason why it is named so has a very interesting history. read more
North and South America are continents. Together, North and South America are called the Americas (not the USA). The USA is a country. The USA is located in North America; The USA is bordered by Canada to the north, Mexico to the south, the Atlantic ocean to the east and the Pacific ocean to the west. Continents are not countries. read more
United States of America means that the United States belongs to America and NOT that America belongs to the United States. So, next time you want to refer to The United States of America, you can do it as U.S. or the States or whatever you want but not as only America. read more