Back of room, one in school? (4)
I believe the answer is:
form
'one in school?' is the definition.
'form' can be an answer for 'school?' (thesaurus). I'm not certain of the 'one in' bit.
'back of room' is the wordplay.
'back' says the letters should be written backwards.
'room' becomes 'rm' (abbreviation for room).
'of' written backwards gives 'fo'.
'fo'+'rm'='FORM'
Can you help me to learn more?
(Other definitions for form that I've seen before include "Class - questionnaire" , "Criminal record (colloq.)" , "A hare's hide-out" , "Acceptable conduct" , "Printed document with blank spaces for information to be inserted" .)