Otoscope target (3)
I believe the answer is:
ear
'otoscope target' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ear that I've seen before include "Auricle" , "Van Gogh missing body part" , "Organ involved with balance" , "Attention; seed head" , "Sense organ" .)