Religious edict located in Istanbul library (4)
I believe the answer is:
bull
'religious edict located' is the definition.
I can't tell whether this definition defines the answer.
'in istanbul library' is the wordplay.
'in' indicates the answer is hidden within the clue.
'BULL' is hidden in the letters of 'istanbul library'.
Can you help me to learn more?
(Other definitions for bull that I've seen before include "Animal on target?" , "Pope's edict" , "Papal edict - nonsense" , "Animal; 23 across" , "Male walrus" .)