Nope, you still have it bass ackwards.
Great Britain is one part of the United Kingdom, long title United Kingdom of Great Britain and Northern Ireland.
The United States is part of America. North America is a continent. A continent is a very, very, very big land mass. The USA is not the only country which is part of America.
You really aren't very smart, are you?
Great Britain: 1 island W Europe comprising England, Scotland, & Wales area 88,150 square miles (228,300 square kilometers), population 53,917,000" (Merriam Webster Dictionary Online).
America: 1a. The United States b. the land mass occupied by the United States 2. North, South, and Central America: a landmass comprising North America, South America, and Central America
My comparison was correct: geographic entity to political entity.