The Collaborative International Dictionary
xiphisternum
Xiphiplastron \Xiph"i*plas"tron\, n.; pl. Xiphiplastra. [NL., fr. Gr. xi`fos a sword + plastron.] (Anat.) The posterior, or fourth, lateral plate in the plastron of turtles; -- called also xiphisternum.
Wiktionary
xiphisternum
n. The xiphoid process, a small cartilaginous extension to the lower part of the sternum, usually ossify in the adult human.