bartisan

noun /bɑːtɪˈzæn/

A parapet with battlements projecting from the top of a tower in a castle or church.

, 1819: she soon found it had no communication with any other part of the battlements, being an isolated bartisan, or balcony, secured, as usual, by a parapet, with embrasures, at which a few archers might be stationed for defending the turret, and flanking with their shot the wall of the castle on that side. — Walter Scott, Ivanhoe