A person who has served his time in some profession: Mildred's uncle was a professor of the university and now he has retired and she is now attending the same academic institution.

The origin of this word comes from Roman military tradition with the meaning of "a soldier who has served his time honorably". Modern usage usually refers to a university officer who is rewarded for faithful service with the position, for example, professor emeritus.

The title of emeritus may allow the person so honored to continue to use the facilities of the institution and to attend ceremonies as an honored member of the academic community.