The Collaborative International Dictionary of English v.0.48:

Intermediary \In`ter*me"di*a*ry\, a. [Cf. F. interm['e]diaire.]
   Lying, coming, or done, between; intermediate; as, an
   intermediary project.
   [1913 Webster]

   Intermediary amputation (Surg.), an amputation for injury,
      performed after inflammation has set in.
      [1913 Webster]