What is the X in X-mas?
a 16c. merger of Middle English pyony (from Old English peonie) and Old North French pione (Modern French pivoine), both from Late Latin peonia, from Latin pæonia, from Greek paionia (fem. of paionios), perhaps from Paion, physician of the gods (or Apollo in this aspect), and so called for the plant's healing qualities. The root, flowers, and seeds formerly were used in medicine.