In an educational setting, a dean is a person with significant authority .
Although most high schools are led by a principal, some (particularly private preparatory schools) refer to their chief authority as a dean.
The term is much more commonly used in higher education. Although usage differs from one institution to another, a dean is usually the head of a significant department or collection of departments within a university. Almost every American law school and medical school refers to their highest ranking administrator as a dean, and most have several assistant or associate deans as well.