A "Professor Emeritus" is a title given to a retired professor who has made significant contributions to their academic field. This honor recognizes their years of service, research, and teaching at a university or college. Although they are no longer actively teaching, they may still engage in research, mentoring, or other academic activities. The title is often associated with prestigious institutions and can be held by professors from various disciplines, including the sciences, humanities, and social sciences. It allows them to maintain a connection to their academic community, often participating in events or serving on committees related to their expertise.