>>Just a phrase, something to lump all those countries between Mexico and South America mainland, but it's definitely not a continent. It's a region spanning the tips of the two Americas.
>
>In school in Argentina long, long time ago we studied America as 3 continents, North America (Canada, US, Mexico), Central America (South of Mexico to Panama + the Caribbean Islands IIRC) and South America.

Geography is a weird mix of physics (from astronomy to meteorology) and politics (including economy). The political divisions may invent continents, or split them into more convenient (for the divider, of course) chunks.

One of the funnier points in the geography I learned was about the shape of Earth. After being allegedly considered flat (which it may not have really been, it could be just Irving Berlin's confabulation), it was considered a sphere, then a slightly flattened sphere, then they tried to include the irregularities such as mountains and ocean bottom... and eventually decided that Earth has a shape of (drum rolling... down the stairs, all the way...) ... a geoid. This literally means "Earth has the shape of a figure which has the shape of Earth".

Some science :).