folk-music (n.)youdaoicibaDictYouDict[folk-music 词源字典]
"music of the people," 1852 (Andrew Hamilton, "Sixteen Months in the Danish Isles"), from folk in the "of the people" sense (also see folklore) + music. Modeled on German Volksmusik. In reference to a branch of modern popular music imitative of the simple and artless style of music originating among the common people (originally associated with Greenwich Village in New York City) it dates from 1958.
Of airs properly national, it should be remembered, the composers are not known. They are found existing among the people, who are ignorant of their origin. They are, to borrow a German phrase, folk-music. [Richard Grant White, "National Hymns," New York, 1861]


The term National Music implies that music, which, appertaining to a nation or tribe, whose individual emotions and passions it expresses, exhibits certain peculiarities more or less characteristic, which distinguish it from the music of any other nation or tribe.*
* The Germans call it Volksmusik, a designation which is very appropriate, and which I should have rendered folk-music, had this word been admissible. [Carl Engel, "An Introduction to the Study of National Music," London, 1866]
[folk-music etymology, folk-music origin, 英语词源]