Misericorde (n) mis·er·i·cord or mis·er·i·corde:
A small, thin dagger, sometimes with a triangular blade, usually carried by knights as an emergency weapon. The name might come from the use of the knife to deliver a killing blow to knights, as the blade was small enough to slip between gaps in the armour. Whether, in this instance, the name refers to the lethality of this death blow, or the ‘mercy’ given by putting an injured, and possibly about to be captured, knight out of its misery is open to debate.