gradual school

In the movie “The World According To Garp” that’s what the younger son, Walt, calls graduate school, where his mom teaches. He says “gradual school” and “gradual student.”

Walt: Daddy what's gradual school?
T. S. Garp: What?
Walt: Gradual school. Mommy say's she teaches at gradual school.
T. S. Garp: Oh Gradual school is where you go to school and you gradually find out you don't want to go to school anymore.