Latin America and South America are not the same thing.
South America is a continent connected by the narrow Isthmus of Panama to the separate continent of North America. South America extends from Colombia to Chile.
To say “South America” is to talk about a geographical entity.
Latin America is a cultural entity. South America is part of it, but so are some North American countries: Mexico, the nations of Central America, and some of the islands of the Caribbean Sea. What makes all these places “Latin American” is that their people speak languages derived from Latin.
Spanish, spoken in most of Latin America, is a Latin-derived language; so are Portuguese, which is spoken in Brazil, and French, which is spoken in Haiti and Martinique.