The Low Countries comprise the coastal Rhine–Meuse–Scheldt delta region in Western Europe, whose definition usually includes the modern countries of Luxembourg, Belgium, the Netherlands and parts of Northern France. Both Belgium and the Netherlands derived their names from earlier names for the region, due to nether meaning "low" and Belgica being the Latinised name for the Low Countries,derived from the ancient Belgae confederation of tribes. a nomenclature that became obsolete after Belgium's secession in 1830.

The Low Countries—and the Netherlands and Belgium—had in their history exceptionally many and widely varying names, resulting in equally varying names in different languages. There is diversity even within languages: the use of one word for the country and another for the adjective form is common. This holds for English, where Dutch is the adjective form for the country "the Netherlands". Moreover, many languages have the same word for both the country of the Netherlands and the region of the Low Countries, e.g., French (les Pays-Bas), Spanish (los Países Bajos) and Portuguese (Países Baixos). The complicated nomenclature is a source of confusion for outsiders, and reflects the long history and the frequent changes in ruling power in the Low Countries over the past 2,000 years.

History The historic Low Countries made up much of Frisia, home to the Frisii, and the Roman provinces of Gallia Belgica and Germania Inferior, home to the Belgae and Germanic peoples like the Batavi. Throughout the centuries, the names of these ancestors have been in use as a reference to the Low Countries, in an attempt to define a collective identity. In the 4th and 5th centuries a Frankish confederation of Germanic tribes significantly made a lasting change by entering the Roman provinces and starting to build the Carolingian Empire, of which the Low Countries formed a core part.

By the 8th century, most of the Franks had exchanged their Germanic Frankish language for the Latin-derived Romances of Gaul. The Franks that stayed in the Low Countries had kept their original language, i.e., Old Dutch, also known as "Old Low Franconian" among linguists. At the time the language was spoken, it was known as *þiudisk, meaning "of the people"—as opposed to the Latin language "of the clergy"—which is the source of the English word Dutch. Now an international exception, it used to have in the Dutch language itself a cognate with the same meaning, i.e., Diets(c) or Duuts(c).

The designation "low" to refer to the region has also been in use many times. First by the Romans, who called it Germania "Inferior". After the Frankish empire was divided several times, most of it became the Duchy of Lower Lorraine in the 10th century, where the Low Countries politically have their origin. Lower Lorraine disintegrated into a number of duchies, counties and bishoprics. Some of these became so powerful, that their names were used as a pars pro toto for the Low Countries, i.e., Flanders, Holland and to a lesser extent Brabant. Burgundian, and later Habsburg rulers added one by one the Low Countries' polities in a single territory, and it was at their francophone courts that the term les pays de par deçà arose, that would develop in Les Pays-Bas or in English "Low Countries" or "Netherlands".

Names derived from theodisc (vernacular)

Dutch, Diets and Duyts

English is one of the only languages to use the adjective Dutch for the language of the Netherlands and Flanders. Its connection to the vernacular can be traced back to the Early Mediaeval Latin term Theodiscus, meaning 'of the people' or 'popular language.' In the Middle Ages, Theodiscus was used to distinguish the spoken language of the common Germanic folk from Latin, which was the language of the church, science, and administration. It served as a way to categorise languages based on their practical and social functions.Random House Webster's Unabridged Dictionary, 2nd revised edn., s.v. "Dutch" (Random House Reference, 2005). The word is derived from Proto-Germanic . The stem of this word, , meant "people" in Proto-Germanic, and was an adjective-forming suffix, of which is the Modern English form., p. 269. was its Latinised form.W. Haubrichs, "Theodiscus, Deutsch und Germanisch - drei Ethnonyme, drei Forschungsbegriffe. Zur Frage der Instrumentalisierung und Wertbesetzung deutscher Sprach- und Volksbezeichnungen." In: H. Beck et al., Zur Geschichte der Gleichung "germanisch-deutsch" (2004), 199–228

It was first recorded in 786, when the Bishop of Ostia writes to Pope Adrian I about a synod taking place in Corbridge, England, where the decisions are being written down "tam Latine quam theodisce" meaning "in Latin as well as Germanic".M. Philippa e.a. (2003–2009) Etymologisch Woordenboek van het Nederlands [diets]Cornelis Dekker: The Origins of Old Germanic Studies in the Low Countries So in this sense theodiscus referred to the Germanic language spoken in Great Britain, which was later replaced by the name Englisc.

By the late 14th century, þēodisc had given rise to Middle English duche and its variants, which were used as a blanket term for all the non-Scandinavian Germanic languages spoken on the European mainland. Historical linguists have noted that the medieval "Duche" itself most likely shows an external Middle Dutch influence, in that it shows a voiced alveolar stop rather than the expected voiced dental fricative. This would be a logical result of the Medieval English wool trade, which brought the English in close linguistic contact with the cloth merchants living in the Dutch-speaking cities of Bruges and Ghent, who at the time, referred to their language as dietsc.P.A.F. van Veen en N. van der Sijs (1997), Etymologisch woordenboek: de herkomst van onze woorden, 2e druk, Van Dale Lexicografie, Utrecht/Antwerpen

Its exact meaning is dependent on context, but tends to be vague regardless.H. Kurath: Middle English Dictionary, part 14, University of Michigan Press, 1952, 1346. When concerning language, the word duche could be used as a hypernym for several languages (The North est Contrey which lond spekyn all maner Duche tonge – The North [of Europe] is an area, in which all lands speak all manner of "Dutch" languages) but it could also suggest singular use (In Duche a rudder is a knyght – In "Dutch" a rudder [cf. Dutch: ridder] is a knight) in which case linguistic and/or geographic pointers need to be used to determine or approximate what the author would have meant in modern terms, which can be difficult.H. Kurath: Middle English Dictionary, part 14, University of Michigan Press, 1952, 1345. For example, in his poem Constantyne, the English chronicler John Hardyng (1378–1465) specifically mentions the inhabitants of three Dutch-speaking fiefdoms (Flanders, Guelders, and Brabant) as travel companions, but also lists the far more general "Dutchemēne" and "Almains", the latter term having an almost equally broad meaning, though being more restricted in its geographical use; usually referring to people and locaties within modern Germany, Switzerland and Austria:

By early 17th century, general use of the word Dutch had become exceedingly rare in Great Britain and it became an exonym specifically tied to the modern Dutch, i.e. the Dutch-speaking inhabitants of the Low Countries. Many factors facilitated this, including close geographic proximity, trade and military conflicts, for instance the Anglo-Dutch Wars.M. Philippa e.a. (2003-2009) Etymologisch Woordenboek van het Nederlands [Duits]L. Weisgerber, Deutsch als Volksname 1953 Due to the latter, "Dutch" also became a pejorative label pinned by English speakers on almost anything they regard as inferior, irregular, or contrary to their own practice. Examples include "Dutch treat" (each person paying for himself), "Dutch courage" (boldness inspired by alcohol), "Dutch wife" (a type of sex doll) and "Double Dutch" (gibberish, nonsense) among others.Rawson, Hugh, Wicked Words, Crown Publishers, 1989.

In the United States, the word "Dutch" remained somewhat ambiguous until the start of the 19th century. Generally, it referred to the Dutch, their language or the Dutch Republic, but it was also used as an informal monniker (for example in the works of James Fenimore Cooper and Washington Irving) for people who would today be considered Germans or German-speaking, most notably the Pennsylvania Dutch. This lingering ambiguity was most likely caused by close proximity to German-speaking immigrants, who referred to themselves or (in the case of the Pennsylvania Dutch) their language as "Deutsch" or "Deitsch", rather than archaic use of the term "Dutch".Hughes Oliphant Old: The Reading and Preaching of the Scriptures in the Worship of the Christian Church, Volume 6: The Modern Age. Eerdmans Publishing, 2007, p. 606.Mark L. Louden: Pennsylvania Dutch: The Story of an American Language. JHU Press, 2006, p.2Irwin Richman: The Pennsylvania Dutch Country. Arcadia Publishing, 2004, p.16.The Pennsylvania Dutch Country, by I. Richman, 2004: "Taking the name Pennsylvania Dutch from a corruption of their own word for themselves, "Deutsch," the first German settlers arrived in Pennsylvania in 1683. By the time of the American Revolution, their influence was such that Benjamin Franklin, among others, worried that German would become the commonwealth's official language."Moon Spotlight Pennsylvania Dutch Country, by A. Dubrovsk, 2004.Pennsylvania Dutch Alphabet, by C. Williamson.

In the Dutch language itself, Old Dutch *thiudisk evolved into a southern variant duutsc and a western variant dietsc in Middle Dutch, which were both known as duytsch in Early Modern Dutch. In the earliest sources, its primary use was to differentiate between Germanic and the Romance dialects, as expressed by the Middle Dutch poet Jan van Boendale, who wrote:J. de Vries (1971), Nederlands Etymologisch Woordenboek

During the High Middle Ages "Dietsc/Duutsc" was increasingly used as an umbrella term for the specific Germanic dialects spoken in the Low Countries, its meaning being largely implicitly provided by the regional orientation of medieval Dutch society: apart from the higher echelons of the clergy and nobility, mobility was largely static and hence while "Dutch" could by extension also be used in its earlier sense, referring to what today would be called Germanic dialects as opposed to Romance dialects, in many cases it was understood or meant to refer to the language now known as Dutch.L. De Grauwe: Emerging Mother-Tongue Awareness: The special case of Dutch and German in the Middle Ages and the early Modern Period (2002), p. 98-110. Apart from the sparsely populated eastern borderlands, there was little to no contact with contemporary speakers of German dialects, let alone a concept of the existence of German as language in its modern sense among the Dutch. Because medieval trade focused on travel by water and with the most heavily populated areas adjacent to Northwestern France, the average 15th century Dutchman stood a far greater chance of hearing French or English than a dialect of the German interior, despite its relative geographical closeness.A. Duke: Dissident Identities in the Early Modern Low Countries (2016) Medieval Dutch authors had a vague, generalised sense of common linguistic roots between their language and various German dialects, but no concept of speaking the same language existed. Instead they saw their linguistic surroundings mostly in terms of small scale regiolects.L. De Grauwe: Emerging Mother-Tongue Awareness: The special case of Dutch and German in the Middle Ages and the early Modern Period (2002), p. 102.

In the 19th century, the term "Diets" was revived by Dutch linguists and historians as a poetic name for Middle Dutch and its literature.M. Janssen: Atlas van de Nederlandse taal: Editie Vlaanderen, Lannoo Meulenhoff, 2018, p. 30.

Nederduits