The Collaborative International Dictionary of English v.0.48:

dissolvent \dis*solv"ent\, a. [L. dissolvens, -entis, p. pr. of
   dissolvere.]
   Having power to dissolve power to dissolve a solid body; as,
   the dissolvent juices of the stomach. --Ray.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dissolvent \Dis*solv"ent\, n.
   1. That which has the power of dissolving or melting other
      substances, esp. by mixture with them; a menstruum; a
      solvent.
      [1913 Webster]

            Melted in the crucible dissolvents.   --A. Smith.
      [1913 Webster]

            The secret treaty of December acted as an immediate
            dissolvent to the truce.              --Mothley.
      [1913 Webster]

   2. (Med.) A remedy supposed capable of dissolving concretions
      in the body, such as calculi, tubercles, etc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dissolvent
    n 1: a liquid substance capable of dissolving other substances;
         "the solvent does not change its state in forming a
         solution" [syn: solvent, dissolvent, dissolver,
         dissolving agent, resolvent]