The most common usage of "xiphiod" is in the anatomical term "xiphoid process", which is the small, cartilaginous projection at the bottom of the sternum (breastbone). Its shape resembles a sword, hence the name.
While "xiphiod" is primarily used in anatomical contexts, it can also be used more generally to describe anything that has a sword-like shape. For example, you might describe a particular type of leaf as "xiphiod" if its shape resembles a sword.