Emeritus is a special title given to professors, clergy, or other professionals when they retire after many years of distinguished service. When a professor becomes professor emeritus, they're no longer teaching regular classes, but the university honors their contributions by letting them keep their professional title.

Think of it as a form of permanent respect. A chemistry professor who spent 35 years teaching and researching might retire as “Professor Emeritus of Chemistry.” This means the university values their decades of work enough to say, “You'll always be one of us.” They might still use the university library, attend important ceremonies, or occasionally give guest lectures, but they're no longer responsible for daily teaching duties.

It's always used after someone retires, never before. You might see “Bishop Emeritus” for a retired bishop, or “Conductor Emeritus” for a retired orchestra leader. The title emeritus says that someone didn't just quit or fade away: they completed a career of such quality that their organization wants to honor that achievement.

The feminine form is emerita, and the plural is emeriti.