Walloon is a Belgian version of an old West Germanic word reconstructed as *walh (“foreigner, stranger, speaker of Celtic or Latin”).

Brabant is from Old Dutch *brākbant (attested in Medieval Latin as pāgus brācbatensis, Bracbantum, Bracbantia), from Frankish, a compound of Proto-Germanic *brēk-, *brekaną (“fallow, originally 'to break'”) + *bant-, *bantō, *banti (“district, region”) Like the terms "Belgium" and "Flanders", the terms "Walloon" and "Brabant" are much older than the modern political entities which they represent today, but were already being used in the region when political boundaries were different.

For example, Louis de Haynin wrote as follows in 1628:[5] De Haynin noted that the distinction people made in his time between Walloon and German or Flemish Belgium was apparently based upon language, with the Walloons speaking French, and the others speaking what he described as a type of Low German (un bas alleman) which people, especially foreigners, referred to as Flemish.

Nivelles District: The regional Gross domestic product (GDP) of the province was 19.3 billion € in 2018, accounting for only 4.2% of Belgium's economic output.

This wealth is at least partly due to the economy of the neighbouring capital city region of Brussels, which is not a province, because many residents of Walloon Brabant are employed there.

For comparison, Brussels had a GDP per capita adjusted for purchasing power of €61,300, equivalent to 203% of the EU average, but unlike Walloon Brabant it is significantly lower, at 161%, when calculated per person employed.

In Rixensart, the company Recherche et Industrie Thérapeutiques (changed to GlaxoSmithKline Biologicals in 2000) is one of the world's leading vaccine manufacturers, supplying around 25% of the world's vaccines: GSK Biologicals employs a little over 5,300 persons on the Walloon sites of Rixensart, Wavre and Gembloux.