Limes (Roman Empire)

"Limes" (plural "limites") is a modern term used for the Roman border defence in Germany. It marks the borders of the Roman Empire, though it was not used by the Romans for this purpose. 
The term has been extended to refer to the frontier defences in other parts of the empire, such as in the east and in Africa. It is used by the World Heritage site bureaucracy to include the two walls in Britain, the Antonine Wall and Hadrian's Wall.
The Limes is often associated with Roman forts, but it could apply to any area near the walls where the Romans exercised loose control with military forces.