'Southwark' means the southern fort.
In the 10th century the Burghal Hidage recorded it as Suthriganaweorc, the defensive work of the men of Surrey; the Domesday Book of 1086 has Sudweca. 'Southern' refers to the City of London to the north: Southwark lies at the southern end of London Bridge. The station is set away from that ancient core, on what would have been marshland for most of its history.