It was named America first, then Brazil and the places to the south were founded. They were then called North America and South America, for one is North and one is South.
No, one thing cannot be larger than itself, since it is the same item. For example, if you have a banana, you cannot say "this banana is much tastier than this banana" (referring to the same banana);...
The United States is a country in North America. America is a general term used for both North and South America, but usually when people say the word "America" they are referring to the USA....