The Collaborative International Dictionary of English v.0.48:

Osculant \Os"cu*lant\, a. [L. osculans, -antis, p. pr. of
   osculari to kiss. See Osculate.]
   [1913 Webster]
   1. Kissing; hence, meeting; clinging.
      [1913 Webster]

   2. (Zool.) Adhering closely; embracing; -- applied to certain
      creeping animals, as caterpillars.
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   3. (Biol.) Intermediate in character, or on the border,
      between two genera, groups, families, etc., of animals or
      plants, and partaking somewhat of the characters of each,
      thus forming a connecting link; interosculant; as, the
      genera by which two families approximate are called
      osculant genera.
      [1913 Webster]