1. Boob(s) that appear in a movie shown in school.
2. Accidental boob(s) that appear in any form of art or media that the teacher forgot about or didn't know about
3. The kind of thing that makes male students go "WOAHHH!" and "AW YEAHHH!"
"Freshmen year, the class watched Romeo and Juliet and it totally had some school boob."
"I don't know if Mr. Smith knew, but that anatomy video showed school boob"
"Why is it necessary for the biology teacher to be showing school boob on her powerpoint presentation?"