Latinoamérica is all Spanish, Portuguese, and French speaking countries in the Americas plus Puerto Rico. Quebec, Louisiana, and Miami are not part of Latinoamérica. Latinoamérican ethnicity is anyone whose culture comes from Latinoamérica. Examples:

People born in Miami aren't Latino. However, if they were raised in a Latino family, then yes.
A person born in Puerto Rico to an Anglo-Saxon family that rarely if ever socialized with the local population wouldn't be Latino.
A person born in Australia to Mexican parents and raised with Mexican culture would be Latino.
A person born in Mexico to an Australian family that acculturated and integrated to the local culture would be Latino.
A person born and raised in Spain as Spanish is not Latino.
French-Canadians are generally not considered Latino because they have been culturally isolated from Latinoamérica.
A person born in Ancient Rome would not have been Latino even if they spoke Latin.

[–] Aedis@lemmy.world 2 points 4 days ago

It's actually much simpler than that. Latino is just someone living in the US that is a descendent of someone from Latin America.

The term might extend to people living in other countries other than the US by now, but the definition is similar.