brisure

noun2

1. •
   A mark of cadency or difference.

   • But the bar (being a horizontal piece, a diminutive of the Fess), is not used like the French barre as a brisure for illegitimacy; a bar-sinister is an absurdity and impossibility. — 1896
2. •
   Any part of a rampart or parapet which deviates from the general direction.