Source : Webster's Revised Unabridged Dictionary (1913)

Interspersion \In`ter*sper"sion\, n.
   The act of interspersing, or the state of being interspersed.

Source : WordNet®

interspersion
     n : the act of combining one thing at intervals among other
         things; "the interspersion of illustrations in the text"
         [syn: {interspersal}]