The Collaborative International Dictionary of English v.0.48:

Flux \Flux\ (fl[u^]ks), n. [L. fluxus, fr. fluere, fluxum, to
   flow: cf.F. flux. See Fluent, and cf. 1st & 2d Floss,
   Flush, n., 6.]
   1. The act of flowing; a continuous moving on or passing by,
      as of a flowing stream; constant succession; change.
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            By the perpetual flux of the liquids, a great part
            of them is thrown out of the body.    --Arbuthnot.
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            Her image has escaped the flux of things,
            And that same infant beauty that she wore
            Is fixed upon her now forevermore.    --Trench.
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            Languages, like our bodies, are in a continual flux.
                                                  --Felton.
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   2. The setting in of the tide toward the shore, -- the ebb
      being called the reflux.
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   3. The state of being liquid through heat; fusion.
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   4. (Chem. & Metal.) Any substance or mixture used to promote
      the fusion of metals or minerals, as alkalies, borax,
      lime, fluorite.
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   Note: White flux is the residuum of the combustion of a
         mixture of equal parts of niter and tartar. It consists
         chiefly of the carbonate of potassium, and is white. --
         Black flux is the ressiduum of the combustion of one
         part of niter and two of tartar, and consists
         essentially of a mixture of potassium carbonate and
         charcoal.
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   5. (Med.)
      (a) A fluid discharge from the bowels or other part;
          especially, an excessive and morbid discharge; as, the
          bloody flux or dysentery. See Bloody flux.
      (b) The matter thus discharged.
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   6. (Physics) The quantity of a fluid that crosses a unit area
      of a given surface in a unit of time.
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