'barbican' originates from Old French, specifically the word 'barbicane', where 'barbicane' referred to a fortified outwork or gatehouse.

'barbican' changed from Medieval Latin/Old French forms such as 'barbecana'/'barbicane' and eventually became the modern English word 'barbican'.

Initially, it meant 'a fortified outwork placed before a gate', and over time it has kept this core sense as 'an outer defence or gatehouse'.