Prefix for "biography" (4)
I believe the answer is:
auto
'prefix for biography' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for auto that I've seen before include "Prefix meaning self or same" , "Motor vehicle, in short" , "Car, in short" , "Prefix to denote self or same" , "Motor car (mainly US)" .)