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