Abbr. in some high school names

I believe the answer is:

prep

(Other definitions for prep that I've seen before include "School work done outside lessons" , "warm-up race" , "Homework (abbr.)" , "Homework (abbrev.)" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.