The Collaborative International Dictionary of English v.0.48:

Instrumentality \In`stru*men*tal"i*ty\, n.; pl.
   Instrumentalities.
   The quality or condition of being instrumental; that which is
   instrumental; anything used as a means; medium; agency.
   [1913 Webster]

         The instrumentality of faith in justification. --Bp.
                                                  Burnet.
   [1913 Webster]

         The discovery of gunpowder developed the science of
         attack and defense in a new instrumentality. --J. H.
                                                  Newman.
   [1913 Webster]