Menstruum \Men"stru*um\, n.; pl. E. Menstruums, L. Menstrua.
   [L. menstruus. See Menstruous.]
   Any substance which dissolves a solid body; a solvent.
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         The proper menstruum to dissolve metal.  --Bacon.
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         All liquors are called menstruums which are used as
         dissolvents, or to extract the virtues of ingredients
         by infusion or decoction.                --Quincy.
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   Note: The use is supposed to have originated in some notion
         of the old chemists about the influence of the moon in
         the preparation of dissolvents. --Johnson.
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