Source : Webster's Revised Unabridged Dictionary (1913)

Diaphysis \Di*aph"y*sis\, n. [Gr. ? a growing through; dia`
   through + ? to bring forth.]
   1. (Bot.) An abnormal prolongation of the axis of
      inflorescence.

   2. (Anat.) The shaft, or main part, of a bone, which is first
      ossified.

Source : WordNet®

diaphysis
     n : the main (mid) section of a long bone [syn: {shaft}]
     [also: {diaphyses} (pl)]