The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

heterogeneous
    adj 1: consisting of elements that are not of the same kind or
           nature; "the population of the United States is vast and
           heterogeneous" [syn: heterogeneous, heterogenous]
           [ant: homogeneous, homogenous]
    2: originating outside the body [syn: heterogenous,
       heterogeneous] [ant: autogenic, autogenous]

Moby Thesaurus II by Grady Ward, 1.0:

92 Moby Thesaurus words for "heterogeneous":
   amalgamated, ambiguous, ambivalent, amphibious, assorted, at odds,
   at variance, blended, combined, complex, composite, compound,
   compounded, conglomerate, contrary, contrasted, contrasting,
   dappled, departing, deviating, deviative, different,
   differentiated, differing, disaccordant, disagreeing, discordant,
   discrepant, discrete, discriminated, disjoined, disparate,
   dissimilar, dissonant, distinct, distinguished, divergent,
   diverging, divers, diverse, diversified, eclectic, equivocal,
   fifty-fifty, half-and-half, in disagreement, inaccordant,
   incompatible, incongruous, inconsistent, inconsonant,
   indiscriminate, inharmonious, intricate, ironic, irreconcilable,
   jumbled, many, many and various, many-sided, medley, mingled,
   miscellaneous, mixed, motley, multifaceted, multifarious,
   multinational, multiracial, of all sorts, patchy, pluralistic,
   poles apart, poles asunder, promiscuous, scrambled, separate,
   separated, several, sundry, syncretic, thrown together,
   unconformable, unequal, unlike, variant, varied, variegated,
   various, varying, widely apart, worlds apart



The Free On-line Dictionary of Computing (30 December 2018):

heterogeneous

   Composed of unrelated parts, different in kind.

   Often used in the context of distributed systems that may be
   running different operating systems or network protocols
   (a heterogeneous network).

   For examples see: interoperable database, middleware.

   Constrast homogeneous.

   (1999-05-06)