London borough; cab (7)
I believe the answer is:
hackney
I believe this is a double definition.
'london borough' is the first definition.
(I know that Hackney is a London borough)
'cab' is the second definition.
(type of horse-drawn carriage)
(Other definitions for hackney that I've seen before include "district of London" , "Carriage for hire" , "A kind of taxi or car for hire" , "Old cab - London borough" , "Wear out" .)