Source : Webster's Revised Unabridged Dictionary (1913)

Midriff \Mid"riff\, n. [AS. midhrif; midd mid, middle + hrif
   bowels, womb; akin to OFries. midref midriff, rif, ref,
   belly, OHG. href body, and to L. corpus body. See {Corpse}.]
   (Anat.)
   See {Diaphragm}, n., 2.

         Smote him into the midriff with a stone. --Milton.

Source : WordNet®

midriff
     n 1: the middle area of the human torso (usually in front);
          "young American women believe that a bare midriff is
          fashionable" [syn: {middle}, {midsection}]
     2: (anatomy) a muscular partition separating the abdominal and
        thoracic cavities; functions in respiration [syn: {diaphragm}]