The term "xiphoid" comes from the Greek word "xiphos", which means "sword" or "straight sword".  The xiphoid process, a small, triangular-shaped bone at the lower end of the sternum, is named after its sword-like appearance. 

The adjective "xiphoid" first appeared in English in the mid-1700s, with the earliest evidence from the Oxford English Dictionary (OED) being from 1747 in the writing of S. Glass.  The term is most commonly used in anatomy to describe the :xiphoid process, the cartilage- and bone-tipped part of the sternum at the bottom of the rib cage.  a borrowing from Latin "xiphoides", ultimately deriving from the Greek word for "sword".  The xiphoid process helps support muscles and ligaments in your chest and abdomen, but it's possible to live without it. It's what healthcare providers call a vestigial structure.

Examples of "xiphoid" used in a sentence: 
"Just to the bottom of the xiphoid process," Ms. Boyle said. 
"Actually, the “lump” is the xiphoid process, the quarter-size cartilaginous end of the bony sternum."
"The two little girls were united from the xiphoid cartilage to the umbilicus." 
"On examination, she had an abdominal protrusion between the xiphoid process and the umbilicus that contained the small bowel." 

Just the facts:

XIPHOID Definition & Meaning - Merriam-Webster

Adjectives for xiphoid - Merriam-Webster

Xiphoid | Definition, Etymology, Synonyms & Antonyms