Wiktionary
n. (context obsolete English) The battlement on the exterior fortification of a castle in northern England and parts of Scotland; a barbican.
Wikipedia
Barmkin, also spelled barmekin or barnekin, is a Scots word which refers to a form of medieval and later defensive enclosure, typically found around smaller castles, tower houses, pele towers, and bastle houses in Scotland, and the north of England. It has been suggested that etymologically the word may be a corruption of the word barbican. The barmkin would have contained ancillary buildings, and could be used to protect cattle during raids.
Examples of places which had barmkins include Halton Castle, Cheshire, Smailholm Tower, Scottish Borders, and Crichton Castle, Midlothian.
Usage examples of "barmkin".
The tower looked deserted and no one was watching the sheep penned just outside the barmkin.
On the main parapet the sun slapped at the face off turrets and battlements, and far below, the castle rose from the bog like a lighthouse on its circling strands of barmkin, park and moat.