A fer-à-loup (French fer à loup, “wolf iron”) is a forestry implement, found in Continental heraldry. In French blazons, it may also be called a hameçon à loup; in German blazons, a wulfsangel; mundane texts also call it a “wolf-claw” or “wolf-trap”. The fer-à-loup is a period charge, found early on in the arms of von Stein or Stain, c.1340 [Zurich 203]; in the arms of von Stein, the charge remains in that form through the end of period [Siebmacher 111].
On other coats, however, the fer-à-loup’s form evolved over time: in some cases, with a solid bar appearing between the blade and its loop; in other cases, being reinterpreted as an axe-head.
The fer-à-loup’s convex cutting edge is to chief by medieval and Society default. See also knife.
Rognvaldr bassi bears: Per saltire gules and Or, a fer-à-loup sable.
Ulfarr MacDhughaill bears: Per pale sable and azure, a fer-a-loup and an orle Or.
Arnþóra of Wemyss bears as a badge: A fer-a-loup inverted gules.