The Collaborative International Dictionary of English v.0.48:

Mixture \Mix"ture\, n. [L. mixtura, fr. miscere, mixtum, to mix:
   cf. F. mixture. See Mix.]
   1. The act of mixing, or the state of being mixed; as, made
      by a mixture of ingredients. --Hooker.
      [1913 Webster]

   2. That which results from mixing different ingredients
      together; a compound; as, to drink a mixture of molasses
      and water; -- also, a medley.
      [1913 Webster]

            There is also a mixture of good and evil wisely
            distributed by God, to serve the ends of his
            providence.                           --Atterbury.
      [1913 Webster]

   3. An ingredient entering into a mixed mass; an additional
      ingredient.
      [1913 Webster]

            Cicero doubts whether it were possible for a
            community to exist that had not a prevailing mixture
            of piety in its constitution.         --Addison.
      [1913 Webster]

   4. (Med.) A kind of liquid medicine made up of many
      ingredients; esp., as opposed to solution, a liquid
      preparation in which the solid ingredients are not
      completely dissolved.
      [1913 Webster]

   5. (Physics & Chem.) A mass of two or more ingredients, the
      particles of which are separable, independent, and
      uncompounded with each other, no matter how thoroughly and
      finely commingled; -- contrasted with a compound and
      solution; thus, gunpowder is a mechanical mixture of
      carbon, sulphur, and niter.
      [1913 Webster]

   6. (Mus.) An organ stop, comprising from two to five ranges
      of pipes, used only in combination with the foundation and
      compound stops; -- called also furniture stop. It
      consists of high harmonics, or overtones, of the ground
      tone.
      [1913 Webster]

   Syn: Union; admixture; intermixture; medley.
        [1913 Webster]

WordNet (r) 3.0 (2006):

mixture
    n 1: (chemistry) a substance consisting of two or more
         substances mixed together (not in fixed proportions and not
         with chemical bonding)
    2: any foodstuff made by combining different ingredients; "he
       volunteered to taste her latest concoction"; "he drank a
       mixture of beer and lemonade" [syn: concoction, mixture,
       intermixture]
    3: a collection containing a variety of sorts of things; "a
       great assortment of cars was on display"; "he had a variety
       of disorders"; "a veritable smorgasbord of religions" [syn:
       assortment, mixture, mixed bag, miscellany,
       miscellanea, variety, salmagundi, smorgasbord,
       potpourri, motley]
    4: an event that combines things in a mixture; "a gradual
       mixture of cultures" [syn: mix, mixture]
    5: the act of mixing together; "paste made by a mix of flour and
       water"; "the mixing of sound channels in the recording
       studio" [syn: mix, commixture, admixture, mixture,
       intermixture, mixing]

Moby Thesaurus II by Grady Ward, 1.0:

235 Moby Thesaurus words for "mixture":
   English horn, admixture, alloy, alloying, amalgam, amalgamating,
   amalgamation, assemblage, assembly, associating, association,
   assortment, balm, balsam, bassoon, blend, blending, block flute,
   bombard, bourdon, brew, building, buildup, cello,
   chemical solution, claribel, clarinet, clarion, collectanea,
   combination, combining, combo, commixture, composite, composition,
   compost, compound, concert flute, concoction, confection,
   conglomerate, conglomeration, constitution, construction,
   contrariety, contrast, cornet, cornopean, cromorna, cymbel,
   decoction, decoctum, departure, deviation, diapason, difference,
   disaccord, disaccordance, disagreement, disconformity,
   discongruity, discordance, discrepancy, discreteness, disparity,
   dissent, dissimilarity, dissonance, distinction, distinctness,
   divergence, divergency, diversity, drops, drug, dulciana,
   electuary, elixir, embodiment, ensemble, ethical drug, fabrication,
   far cry, farrago, fashioning, flute stop, formation,
   foundation stop, fourniture, fusing, fusion, gallimaufry, gamba,
   gedeckt, gemshorn, generic name, getup, goulash, harmonic flute,
   hash, herbs, heterogeneity, hodgepodge, hybrid stop, immixture,
   inaccordance, incompatibility, incongruity, inconsistency,
   inconsonance, incorporation, inequality, infusion, inhalant,
   inharmoniousness, inharmony, interfusion, intermingling,
   intermixture, interweaving, irreconcilability, jumble, junction,
   koppel flute, larigot, leach, leachate, lincture, linctus,
   lixivium, magma, make, makeup, materia medica, medicament,
   medication, medicinal, medicinal herbs, medicine, medley, melange,
   melodia, merger, merging, mess, mingling, miscellanea, miscellany,
   mishmash, mix, mix-up, mixing, mutation stop, nazard,
   nonconformity, nonprescription drug, oboe, octave, oddments, odds,
   odds and ends, officinal, olio, olla podrida, omnium gatherum,
   omnium-gatherum, opposition, organ stop, organization, otherness,
   paste, patent medicine, pharmacon, physic, piccolo,
   piecing together, plein jeu, posaune, powder, preparation,
   prescription drug, principal, proprietary, proprietary medicine,
   proprietary name, putting together, quint, quintaten, ragout, rank,
   ranket, reed stop, register, rohr flute, salmagundi, separateness,
   sesquialtera, setup, shaping, shawm, simples, solution,
   spitz flute, stop, stopped diapason, stopped flute,
   string diapason, string stop, structure, structuring, sundries,
   syneresis, synthesis, syrup, theraputant, tierce, tisane, tremolo,
   trombone, trumpet, twelfth, unconformity, unda maris, unlikeness,
   unorthodoxy, variance, variation, variegation, variety,
   vegetable remedies, vibrato, viola, voix celeste, vox angelica,
   vox humana