Dutch word kerstbal comes from Dutch bal, Dutch kerst (Christmas.)

Detailed word origin of kerstbal

Dictionary entry	Language	Definition
bal	Dutch (nld)	Ball, dance party (informal) testicle, nut. (informal, pejorative) toff, posh person. (sports) pass, shot. A ball or any object with such a shape.
kerst	Dutch (nld)	Christmas.
kerstbal	Dutch (nld)	A bauble, spherical decoration, commonly used for Christmas decorations, especially Christmas trees.