The Collaborative International Dictionary of English v.0.48:

Medullary \Med"ul*la*ry\, a. [L. medullaris, fr. medulla marrow:
   cf. F. m['e]dullaire.]
   1. (Anat.)
      (a) Pertaining to, consisting of, or resembling, marrow or
          medulla.
      (b) Pertaining to the medula oblongata.
          [1913 Webster]

   2. (Bot.) Filled with spongy pith; pithy.
      [1913 Webster]

   Medullary groove (Anat.), a groove, in the epiblast of the
      vertebrate blastoderm, the edges of which unite, making a
      tube (the medullary canal) from which the brain and spinal
      cord are developed.

   Medullary rays (Bot.), the rays of cellular tissue seen in
      a transverse section of exogenous wood, which pass from
      the pith to the bark.

   Medullary sheath (Anat.), the layer of white semifluid
      substance (myelin), between the primitive sheath and axis
      cylinder of a medullated nerve fiber.
      [1913 Webster]