Birds in City of London street (7)
I believe the answer is:
poultry
'birds in city of london street' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
This is all the clue.
Can you help me to learn more?
(Other definitions for poultry that I've seen before include "Hens, ducks, etc." , "Domestic fowl" , "'Chickens and ducks, say (7)'" , "Domestic fowls as food source" .)