The Collaborative International Dictionary of English v.0.48:

Blend \Blend\ (bl[e^]nd), v. t. [imp. & p. p. Blended or
   Blent (bl[e^]nt); p. pr. & vb. n. Blending.] [OE.
   blenden, blanden, AS. blandan to blend, mix; akin to Goth.
   blandan to mix, Icel. blanda, Sw. blanda, Dan. blande, OHG.
   blantan to mis; to unknown origin.]
   1. To mix or mingle together; esp. to mingle, combine, or
      associate so that the separate things mixed, or the line
      of demarcation, can not be distinguished. Hence: To
      confuse; to confound.
      [1913 Webster]

            Blending the grand, the beautiful, the gay.
                                                  --Percival.
      [1913 Webster]

   2. To pollute by mixture or association; to spoil or corrupt;
      to blot; to stain. [Obs.] --Spenser.
      [1913 Webster]

   Syn: To commingle; combine; fuse; merge; amalgamate;
        harmonize.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

blended \blended\ adj.
   1. combined or mixed together so that the constituent parts
      are indistinguishable. Antonym of unblended. [Narrower
      terms: alloyed; emulsified; homogenized]

   Syn: mingled, commingled.
        [WordNet 1.5]

   2. homogeneous heterogeneous
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

blended
    adj 1: combined or mixed together so that the constituent parts
           are indistinguishable [ant: unblended]

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "blended":
   accordant, according, amalgamated, ambiguous, ambivalent,
   amphibious, assimilated, assonant, assonantal, attuned, blending,
   chiming, combinative, combinatory, combined, complex, composite,
   compound, compounded, concordant, conglomerate, conjoint,
   conjugate, conjunctive, connective, consolidated, consonant,
   dappled, eclectic, equivocal, fifty-fifty, fused, half-and-half,
   harmonic, harmonious, harmonizing, heterogeneous, homophonic,
   in accord, in chorus, in concert, in concord, in sync, in tune,
   in unison, incorporated, indiscriminate, integrated, intricate,
   ironic, joined, joint, jumbled, many-sided, medley, merged,
   mingled, miscellaneous, mixed, monodic, monophonic, motley,
   multifaceted, multinational, multiracial, one, patchy, pluralistic,
   promiscuous, scrambled, symphonious, synchronized, synchronous,
   syncretic, syncretistic, syncretized, synthesized, thrown together,
   tuned, unisonant, unisonous, united, varied