To English speakers outside North America, the term
America means first and foremost the USA, and
North America is used to denote a larger geographical area including also Canada and Mexico. The terms
American and
North American are used correspondingly as adjectives and nouns.
Central America refers to the countries in the narrow strip of land to the south of Mexico (including Guatemala, Nicaragua, and Panama), and
South America to the region to the south of the Panama Canal, including Argentina, Brazil, Chile, Colombia, etc.