Yeah... I learned Spanish in Mexico as a wee lad, the folk living North of there were called "Gringos" or "Yankees". Back in Europe, behind the iron curtain, it was "Americaniard" or "Yank", rarely "American"... even when people meant no disrespect.

Then in Spain... (@PRUSSIA_x86@lemmy.world, you may want to see this)... "American" refers to any citizen of the whole continent... even the official dictionary itself, in it's latest update, actually states:

debe evitarse el empleo de americano para referirse exclusivamente a los habitantes de los Estados Unidos, uso abusivo que se explica por el hecho de que los estadounidenses utilizan a menudo el nombre abreviado América (en inglés, sin tilde) para referirse a su país. No debe olvidarse que América es el nombre de todo el continente y son americanos todos los que lo habitan.

https://www.rae.es/dpd/Estados%20Unidos

The use of American to refer exclusively to the inhabitants of the United States should be avoided, an abusive use that is explained by the fact that Americans often use the abbreviated name America (in English, without accent) to refer to their country. It should not be forgotten that America is the name of the entire continent and all those who inhabit it are Americans.

So yeah, kind of like nicknames... but then some places have different rules about the nicknames. 😉

(...and then there are the actually vulgar despective nicknames, which I won't get into here)