is a blanket term covering several modern Latin peoples descending from the Latinised population in Central, Eastern and Southeastern Europe...
The word Vlach is ultimately of Germanic origin, from the word Walha, "foreigner", "stranger", a name used by ancient Germanic peoples to refer to Romance-speaking and Celtic neighbours. It is possibly derived from the name of the Celtic tribe which was known to the Romans as Volcae (in the writings of Julius Caesar) and to the Greeks as Ouólkai (Strabo and Ptolemy). As such, it shares its history with several ethnic names all across Europe, including the Welsh and Walloons. This word for Romanic people was borrowed from the Germanic Goths (as *walhs) into Proto-Slavic some time before the 7th century. The first source using the word was the writings of Byzantine historian Kedrenos, from the mid-11th century. From the Slavs the term passed to other peoples, such as the Hungarians ("oláh", referring to Vlachs, more specifically Romanians, "olasz", referring to Italians) and Byzantines ("Βλάχοι", "Vláhi") and was used for all Latin people of the Balkans.
...and the Vlachs are all being well considered descendants of Romanised peoples of the area (incl. Thracians, Dacians and Illyrians).
is a reconstructed Proto-Germanic word, meaning "foreigner", "stranger", "Roman", "Romance-speaker", or "Celtic-speaker". The term was used by the ancient Germanic peoples to describe inhabitants of the former Roman Empire, who were largely romanised and spoke Latin or Celtic languages. The adjectival form is attested in Old Norse valskr, meaning "French", Old High German walhisk, meaning "Romance", Modern German welsch, used in Switzerland for Romance-speakers, Old English welisċ, wælisċ, wilisċ, meaning "Romano-British", and Modern English Welsh. The form of these words imply that they are descended from a Proto-Germanic form *walhiska-.