The story
- Proto-Indo-European*bʰelǵʰ-?
- Proto-Celtic*belgos
- LatinBelgae
- DutchBelg
- DutchBelgië
- Old Dutchnither
- Middle Dutchnēder
- Dutchneder
- Proto-Indo-European*lendʰ-
- Proto-Germanic*landą
- Frankish*land
- Old Dutchlant
- Middle Dutchlant
- Dutchland
- DutchNederland
- DutchLuxemburg
- DutchBenelux
- English todayBenelux
Borrowed from Dutch Benelux. By surface analysis, syllabic abbreviation of Belgium + Netherlands + Luxembourg.
Etymology from Wiktionary, CC BY-SA 4.0.