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!"
"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?"