The Collaborative International Dictionary of English v.0.48:

Misericorde \Mis"er*i*corde"\, n. [F. mis['e]ricorde. See
   Misericordia.]
   [1913 Webster]
   1. Compassion; pity; mercy. [Obs.]
      [1913 Webster]

   2. (Anc. Armor.) Same as Misericordia, 2.
      [1913 Webster]

The Devil's Dictionary (1881-1906):

MISERICORDE, n.  A dagger which in mediaeval warfare was used by the
foot soldier to remind an unhorsed knight that he was mortal.