Rise of Little Dorothy Fox (3)
I believe the answer is:
tod
'fox' is the definition.
(historic term)
'rise of little dorothy' is the wordplay.
'rise of' says the letters should be written backwards (in a down clue, letters go up).
'little dorothy' becomes 'dot' (nickname for Dorothy).
'dot' backwards is 'TOD'.
(Other definitions for tod that I've seen before include "One's alone on this" , "Fox" , "Sly person" , "If you're on it, you're on your own" , "Former English weight for wool - dot it" .)