Editor’s note (4)
I believe the answer is:
stet
'editor's note' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stet that I've seen before include "'In printing, cancel a correction and leave it as it was (4)'" , "Let it stand - printer's mark" , "cancel amendment" , "Instruction to keep" , "Leave in, as text" .)