The Collaborative International Dictionary of English v.0.48:

Interosculant \In`ter*os"cu*lant\, a.
   1. Mutually touching or intersecting; as, interosculant
      circles.
      [1913 Webster]

   2. (Biol.) Uniting two groups; -- said of certain genera
      which connect family groups, or of species that connect
      genera. See Osculant.
      [1913 Webster]