Source : Webster's Revised Unabridged Dictionary (1913)

Pineal \Pi"ne*al\, a. [L. pinea the cone of a pine, from pineus
   of the pine, from pinus a pine: cf. F. pin['e]ale.]
   Of or pertaining to a pine cone; resembling a pine cone.

   {Pineal gland} (Anat.), a glandlike body in the roof of the
      third ventricle of the vertebrate brain; -- called also
      {pineal body}, {epiphysis}, {conarium}. In some animals it
      is connected with a rudimentary eye, the so-called pineal
      eye, and in other animals it is supposed to be the remnant
      of a dorsal median eye.

Source : WordNet®

pineal
     adj 1: relating to the pineal body; "pineal hormone"
     2: having the form of a pine cone