when do you call a teacher a professor
Professor In most systems of academic ranks the word "professor", and particularly the unqualified word, only refers to the most senior academic position, sometimes informally known as "full professor".[2][3] In some countries or institutions, the word professor is also used in titles of lower ranks such as associate professor and assistant professor; this is particularly the case in the United States, where the word professor is sometimes used colloquially to refer to anyone in an academic post.[4] This colloquial usage would be considered incorrect nearly everywhere else.