xiphisternum

noun

Etymology: Ancient Greek ξίφος (xíphos, “sword”) + English -i- (in place of the etymologically consistent -o-) + English sternum

1. Synonym of xiphoid process.

   “Hence the spaces between the forks of the hyposternum and between the hypo- and xiphisternums are relatively much smaller, and the external process of the hyposternum is twice as broad as in the common Cock.”

   “1887, "Skeleton", entry in The Encyclopædia Britannica, Volume 22, 9th Edition, page 113, The xiphisternum may assume various forms, but attains its maximum development in Birds, where it forms the part of the sternum posterior to the attachment of the ribs, and may consist of a median and four lateral processes, as in the Fowl. It bears the greater part of the keel.”