The Collaborative International Dictionary of English v.0.48:
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. [1913 Webster] 2. (Anat.) The shaft, or main part, of a bone, which is first ossified. [1913 Webster]WordNet (r) 3.0 (2006):
diaphysis n 1: the main (mid) section of a long bone [syn: diaphysis, shaft]