A usually small and narrow street or alley, especially one in inferior or poorer parts of a city, away from the centre
The back streets of a town or city are the areas of small, old, poor streets rather than the richer or newer areas. the back streets of Berlin
A back street in a town or city is a small, narrow street with very little traffic. The small church of San Michel is tucked away in a narrow back street of Port-au-Prince. backstreet garages
Back street activities are carried out unofficially, secretly, and often illegally. back street abortions
backstreet activities are done in a secret or illegal way, and are often done badly. 'back street a small quiet street that is away from the main part of a town