Webster's Revised Unabridged Dictionary · 1913

Xiphisternum

Xiphisternum , noun

[New Latin, from Greek xi`fos a sword + sternum.]

(a)
(Anatomy) The posterior segment, or extremity, of the sternum; -- sometimes called metasternum, ensiform cartilage, ensiform process, or xiphoid process.
(b)
(Anatomy) The xiphiplastron.