"Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, professor derives from Latin ...
[Read more]
as a "person who professes" being usually an expert in arts or sciences, a teacher of the highest rank.
In most systems of academic ranks the word "professor" only refers to the most senior academic position, sometimes informally known as "full professor". 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. This colloquial usage would be considered incorrect among most other academic communities. However, the unqualified title Professor designated with a capital letter usually refers to a full professor also in English language usage." - (en.wikipedia.org 21.09.2019)
