Pooch in Oz (4)
I believe the answer is:
toto
'pooch in oz' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for toto that I've seen before include "member of the 5d band" , "Famous film dog" , "Dorothy's dog in The Wizard of Oz" , "[FRIEND OF DOROTHY]" .)