The Collaborative International Dictionary of English v.0.48:

Decomposite \De`com*pos"ite\, a. [Pref. de- (intens.) +
   composite.]
   1. Compounded more than once; compounded with things already
      composite.
      [1913 Webster]

   2. (Bot.) See Decompound, a., 2.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Decomposite \De`com*pos"ite\, n.
   Anything decompounded.
   [1913 Webster]

         Decomposites of three metals or more.    --Bacon.
   [1913 Webster]