Source : Webster's Revised Unabridged Dictionary (1913)

Kissingcrust \Kiss"ing*crust`\, n. (Cookery)
   The portion of the upper crust of a loaf which has touched
   another loaf in baking. --Lamb.

         A massy fragment from the rich kissingcrust that hangs
         like a fretted cornice from the upper half of the loaf.
                                                  --W. Howitt.