Source : Webster's Revised Unabridged Dictionary (1913)

Heterogeneous \Het`er*o*ge"ne*ous\, a. [Gr. ?; ? + ? race, kind;
   akin to E. kin: cf. F. h['e]t['e]rog[`e]ne.]
   Differing in kind; having unlike qualities; possessed of
   different characteristics; dissimilar; -- opposed to
   homogeneous, and said of two or more connected objects, or of
   a conglomerate mass, considered in respect to the parts of
   which it is made up. -- {Het`er*o*ge"ne*ous*ly}, adv. --
   {Het`er*o*ge"ne*ous*ness}, n.

   {Heterogeneous nouns} (Gram.), nouns having different genders
      in the singular and plural numbers; as, hic locus, of the
      masculine gender in the singular, and hi loci and h[ae]c
      loca, both masculine and neuter in the plural; hoc
      c[ae]lum, neuter in the singular; hi c[ae]li, masculine in
      the plural.

   {Heterogeneous quantities} (Math.), such quantities as are
      incapable of being compared together in respect to
      magnitude, and surfaces and solids.

   {Heterogeneous surds} (Math.), surds having different radical
      signs.

Source : WordNet®

heterogeneousness
     n : the quality of being diverse and not comparable in kind
         [syn: {heterogeneity}] [ant: {homogeneity}]