[juanito]

I know it's very confusing to a lot of people, but USA stands for United States of America. It's also the only country in the world that has America in its name.

[GFischer]

Ironically it's not the only United States in America (but it is the only one with America in the name I believe)

Mexico is the United States of Mexico, there also were United States of Colombia, United States of Venezuela (now renamed to simply Venezuela), etc...

https://en.wikipedia.org/wiki/Mexico (Wikipedia doesn't show the official name in the title)

https://en.wikipedia.org/wiki/United_States_of_Colombia

https://en.wikipedia.org/wiki/United_States_of_Venezuela