What is American?

Is being American is to divide us from other countries. To have a rights and privileges here in a America. Is American an ethic group because there's a North America and a South America. But I only here people from the U.S. say they are americans. Canada and Mexico is a part of North America, yet they call themselves Canadians and Mexicans instead of Americans. So why are we the only ones who call ourselves Americans.

Another topic I want to bring up is why our so called leader is called a President? Other countries have kings and queens, dictators, and even emperors. So why are we the only ones here in America call our leader a president. Presidents are owners and leaders of companies, cooperation, and industries. So when i think of the President of United States of America, I think of America as not a free country, but a cooperation to raise money.