Source : Webster's Revised Unabridged Dictionary (1913)

Admixture \Ad*mix"ture\ (?; 135), n. [L. admiscere, admixtum, to
   admix; ad + miscere to mix. See {Mix}.]
   1. The act of mixing; mixture.

   2. The compound formed by mixing different substances
      together.

   3. That which is mixed with anything.

Source : WordNet®

admixture
     n 1: the state of impairing the quality or reducing the value of
          something [syn: {alloy}]
     2: an additional ingredient that is added by mixing with the
        base; "the growing medium should be equal parts of sand
        and loam with an admixture of peat moss and cow manure";
        "a large intermixture of sand" [syn: {intermixture}]
     3: 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}, {mixture}, {intermixture},
         {mixing}]