Portuguese medieval fortification nomenclature uses barbican to describe any wall outside of and lower than the main defensive wall that forms a second barrier. The barrier may be complete, extensive or only protect particularly weak areas. The more restrictive term gate barbican is used for structures protecting gates. Islamic world
Aldgate (/ ˈ ɔː l ɡ eɪ t /) was a gate in the former defensive wall around the City of London.It gives its name to Aldgate High Street, the first stretch of the A11 road, which included the site of the former gate.