[edgecasestdio]

This wouldn't just be the US. In Spanish-speaking countries (though technically America as in North/Central/South America), "profesor" can refer to either a high school educator or a university professor: https://www.spanishdict.com/translate/profesor

However, there are nuances. The term "catedrático" is used for senior profesors/profesores at a university: https://spanish.stackexchange.com/questions/21816/what-is-th...

I would be glad to hear more from native Spanish speakers or other foreign language speakers who use similar terms (e.g. French speakers, who also use the word "professeur" with a similar usage).

[Hublium]

Adressing high school teachers as "professor" is common in Austria and Czechia.

[badpun]

Same in Polish. But, in the higher education context, "professor" is the highest job title there is (it's even given by the country's president during an official ceremony, although there's also "university professor" title, which doesn't involve the president), requiring usually at least 15-year academic career.