The origin of words: FOLK

Folk dates back to before the year 900.
The Old and Middle English noun folc could mean ‘common or lay people,’ ‘men,’ ‘a people, nation or tribe,’ ‘a multitude,’ ‘an army’ or ‘a troop.’ It comes from the Proto-Germanic folkam, and further back to the Proto-Indo-European root pele– (to fill). It is related to the Old Saxon folc, the Old Frisian folk, the Middle Dutch volc, the Dutch volk, the Old High German folc and the German Volk, all of which mean ‘people,’ as well as the Old Norse folk (‘people,’ but also also ‘army or detachment’), the Lithuanian pulkas (crowd), and the Old Church Slavonic pluku (division of an army). Through its PIE origin, it is also related to the Greek plethos (people or multitude) and the Latin plebes (the populace, the common people), making it indirectly related to the English word people. Folk was always considered a collective noun until around the 15th century, when it developed a plural, folks, which is more common in the US than in the UK. The adjective use dates back to before the year 900, but only as part of compounds, such as folccwide (popular saying) o folcgemot (town meeting). The modern use of folk as an adjective dates back to the mid-19th century. The use of folks as an informal way to say family developed from a shortened form of kinfolk (early 19th century; kinmeant family, and folk people).