Professor is a full time teaching position or staff in University. Under equal opportunity, professors are being classified. The minimum requirements for the professor job, he/she must hold the PhD degree from any accredited colleges or universities. For those who don't have the PhD degree are lecturers. It was, less than 5 years is associate professor, 5-10 years is professor, and possibly senior professors is more than 10 years. A distinguished professor may have some contribution or works outside his/her teaching job. Possibly, more reaearch than teaching.

A senior professor is a full, or tenured professor - one who has been at the position of professor for about 4-8 years (at most western universities. Tenured professors generally have the position until retirement. It is very rare that one is ever dismissed. A distinguished professor is one whose position has been funded by some source outside the university and independent of it.