An academic position in universities and other post-secondary education and research institutions in the majority of nations is that of professor (often abbreviated as Prof). "A person who proclaims" is how the term professor literally translates from Latin. In most cases, professors are specialists in their fields and are also the best instructors in their schools.
Generally speaking, "professor" is reserved for the most senior academic post, which is occasionally referred to as "full professor" in certain systems of academic ranking. In some countries and institutions, the term "professor" is also used to refer to lower-level positions such as associate professor and assistant professor; this is particularly true in the United States, where the unqualified term is also used colloquially to refer to associate and assistant professors as well as professors of higher education. Among other academic circles, this use might be deemed improper. However, the unqualified title "Professor," which is denoted by a capital letter, almost usually refers to a full professor in the academic hierarchy of the institution.