brisure
Any part of a rampart or parapet which deviates from the general direction.
A mark of cadency or difference.
The baton is made now very short by the French, who call it baton peri, and is always a brisure, frequently made use of by the younger sons of France, of which I have treated in my marks of cadency, and shall do so again[…]
Where it comes from
From French brisure, from briser (“to break”).
Adapted from the Wiktionary entry brisure (CC BY-SA 4.0).