A medieval barbican.
a defensive tower or similar fortification at a gate or bridge leading into a town or castle
Origin of barbicanMiddle English ; from Old French barbacane ; from Medieval Latin barbacana, ; from uncertain or unknown; perhaps
A tower or other fortification on the approach to a castle or town, especially one at a gate or drawbridge.
Origin of barbicanMiddle English, from Old French barbacane, from Medieval Latin barbacana, from Persian barbārkhān : barbār, guard (from Old Iranian *parivāraka-, protective; see wer-4 in Indo-European roots) + khān, house (from Middle Persian).