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}. [1913 Webster]