What is the X in X-mas?
c.1300, "plate of armor," probably from Middle Low German splinte, splente "thin piece of iron," related to Middle Dutch splinte "splint," probably ultimately from PIE *(s)plei- "to split, splice" (see flint). Cognate with Danish splint "splinter," Swedish splint "wooden peg, wedge." Meaning "slender flexible slip of wood" is recorded from early 14c.; specific surgical sense is attested from c.1400.
A rigid device used to prevent motion of a joint or of the ends of a fractured bone.
A dental appliance put on the teeth to protect them from grinding or from moving out of place.