The Collaborative International Dictionary of English v.0.48:

Mix \Mix\ (m[i^]ks), v. t. [imp. & p. p. Mixed (m[i^]kst)
   (less properly Mixt); p. pr. & vb. n. Mixing.] [AS.
   miscan; akin to OHG. misken, G. mischen, Russ. mieshate, W.
   mysgu, Gael. measg, L. miscere, mixtum, Gr. mi`sgein,
   migny`nai, Skr. mi[,c]ra mixed. The English word has been
   influenced by L. miscere, mixtum (cf. Mixture), and even
   the AS. miscan may have been borrowed fr. L. miscere. Cf.
   Admix, Mash to bruise, Meddle.]
   1. To cause a promiscuous interpenetration of the parts of,
      as of two or more substances with each other, or of one
      substance with others; to unite or blend into one mass or
      compound, as by stirring together; to mingle; to blend;
      as, to mix flour and salt; to mix wines.
      [1913 Webster]

            Fair persuasions mixed with sugared words. --Shak.
      [1913 Webster]

   2. To unite with in company; to join; to associate.
      [1913 Webster]

            Ephraim, he hath mixed himself among the people.
                                                  --Hos. vii. 8.
      [1913 Webster]

   3. To form by mingling; to produce by the stirring together
      of ingredients; to compound of different parts.
      [1913 Webster]

            Hast thou no poison mixed?            --Shak.
      [1913 Webster]

            I have chosen an argument mixed of religious and
            civil considerations.                 --Bacon.
      [1913 Webster]

   4. To combine (two or more activities) within a specified or
      implied time frame; as, to mix studying and partying while
      at college.
      [PJC]

WordNet (r) 3.0 (2006):

mixing
    n 1: 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:

43 Moby Thesaurus words for "mixing":
   FCC, FM broadcasting, Federal Communications Commission, admixture,
   alloyage, amalgamation, blending, broadcasting, coalescence,
   combination, comminglement, commingling, commixture, composition,
   eclecticism, fade-out, fusion, immixture, integration, interfusion,
   interlaced scanning, interlarding, interlardment, interminglement,
   intermingling, intermixture, merger, mingling, mixture, monitoring,
   pluralism, radiobroadcasting, scanning, shading,
   standard broadcasting, switching, syncretism, telecasting,
   televising, tone control, transmission, vestigial transmission,
   volume control