TZ database includes "America/Santiago" and "America/Sao_Paulo" so clearly it means the continent and not just the US.
https://en.wikipedia.org/wiki/Continent
Definitions do indeed vary, but that's how I learned it, and it would even seem to be the model most often taught.
Which way were you taught?
TZ database includes "America/Santiago" and "America/Sao_Paulo" so clearly it means the continent and not just the US.