They're taken by students (5)
I believe the answer is:
notes
'they're taken by students' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for notes that I've seen before include "Marks on a stave" , "Recorded summaries" , "registers?" , "Short missives" , "Doh, re, mi, ..." .)