Dutch word drieluik comes from Dutch luik, Dutch drie ((cardinal) three.)

Detailed word origin of drieluik

Dictionary entry	Language	Definition
luik	Dutch (nld)	(arts) panel, as in a triptych. (figuratively) first-rank section, part (of few), e.g. chapter of a plan. Hatch. Shutter.
drie	Dutch (nld)	(cardinal) three.
drieluik	Dutch (nld)	Trilogy. Triptych.