Punishment in school rules (5)
I believe the answer is:
lines
I believe this is a triple definition!
'punishment' is the first definition.
(writing the same thing over and over)
'in' is a link.
'school' is the second definition.
(thesaurus)
'rules' is the third definition.
(I've seen this in another clue)
(Other definitions for lines that I've seen before include "Skin wrinkles" , "Wrinkles; rail tracks" , "Marks" , "Long thin strokes" , "Items" .)