Source : Webster's Revised Unabridged Dictionary (1913)

Epiphysis \E*piph"y*sis\, n.; pl. {Epiphyses}. [NL., fr. Gr.
   'epi`fysis, fr. 'epify`ein to grow upon; 'epi` upon + fy`ein
   to grow.] (Anat.)
   (a) The end, or other superficial part, of a bone, which
       ossifies separately from the central portion, or
       {diaphysis}.
   (b) The cerebral epiphysis, or pineal gland. See {Pineal
       gland}, under {Pineal}.

Source : WordNet®

epiphysis
     n 1: the end of a long bone; initially separated from the main
          bone by a layer of cartilage that eventually ossifies so
          the parts become fused
     2: a small endocrine gland in the brain; situated beneath the
        back part of the corpus callosum; secretes melatonin [syn:
         {pineal gland}, {pineal body}, {epiphysis cerebri}]
     [also: {epiphyses} (pl)]